diff --git a/NEWS.adoc b/NEWS.adoc
index 8da073ce8e..1b94f39259 100644
--- a/NEWS.adoc
+++ b/NEWS.adoc
@@ -122,6 +122,41 @@ https://github.com/networkupstools/nut/milestone/13
       rate, data bits, parity, stop bits, flow control, per-byte read timeout,
       and transmission pacing. Also improved serial resource handling and
       reconnection behavior. [issue #3510, PR #3543]
+    * Reworked incoming serial framing to use the total packet length declared
+      by byte `[1]`, instead of treating every `0xFF` as a new packet and every
+      `0xFE` as its end. A leading `0xFF` now starts a frame only while the
+      reader is idle; subsequent `0xFF` and `0xFE` values are preserved as
+      payload or checksum data. The frame is completed at its declared length
+      and accepted only when that final byte is `0xFE`. Declared lengths are
+      also bounded by the receive buffer before further bytes are stored.
+      This prevents valid 18-byte and 50-byte HWINFO replies containing an
+      internal `0xFF` from being split into unrecognized fragments, allowing
+      the driver to obtain model, firmware, serial number and battery-pack
+      information instead of repeatedly requesting HWINFO and delaying normal
+      polling. The raw packet captures and protocol analysis which made this
+      correction possible were contributed by GitHub user `freechurros`.
+      [issue #3592]
+    * Applied follow-up hardware-test feedback from `freechurros`: corrected
+      `interpret_pkt_hwinfo()` to validate the HWINFO checksum instead of the
+      DATA checksum, exposed unrecognized packets through `debug_pkt_raw`, and
+      published the documented lower-case `battery.charger.status` values for
+      compatibility with Home Assistant. [issue #3592]
+    * Send the long, short and compatibility hardware-discovery requests from
+      `upsdrv_initinfo()`, checking the serial descriptor before every request.
+      Failed or partial writes now mark data stale and invalidate the port so
+      the normal update cycle reopens it before further communication.
+    * Refresh cached model-specific data from every valid HWINFO packet and
+      restart discovery after a serial reconnection, allowing a replaced UPS
+      to be identified without restarting the driver.
+    * Added the legacy five-byte compatibility initialization request
+      (`FF 05 01 06 FE`) as a third fallback. The driver first makes six
+      extended initialization attempts, then selects randomly among the
+      extended, normal and compatibility requests so older or otherwise
+      compatibility-dependent NHS units can answer with their supported
+      protocol variant.
+    * Consolidated the NHS model-code metadata into an indexed lookup table,
+      preserving the existing model descriptions and nominal VA mappings while
+      making unknown-code handling explicit.
 
  - `nutdrv_qx` driver updates:
     * Added the `richcomm-svc` USB communication subdriver for older
diff --git a/docs/nut.dict b/docs/nut.dict
index 2fb4a9e1da..4d9fdcf5cd 100644
--- a/docs/nut.dict
+++ b/docs/nut.dict
@@ -2238,6 +2238,7 @@ fosshost
 fp
 fprintf
 freebsd
+freechurros
 freedesktop
 freeipmi
 freetype
@@ -3758,6 +3759,7 @@ xAAAA
 xCC
 xD
 xF
+xFE
 xFF
 xXXXX
 xYYYY
diff --git a/drivers/nhs_ser.c b/drivers/nhs_ser.c
index 79e7d9e027..0bc6f6af31 100644
--- a/drivers/nhs_ser.c
+++ b/drivers/nhs_ser.c
@@ -229,16 +229,22 @@ typedef struct {
 	unsigned int	upscode;
 	char		upsdesc[100];
 	unsigned int	VA;
+	/* Protocol generation associated with the model; currently informational. */
+	unsigned int	pversion;
+	/* Set to 1 to publish the received bypass bit as a NUT alarm. */
+	unsigned int	bypassasalarm;
 } upsinfo;
 
 static const unsigned int	string_initialization_long[9] = {0xFF, 0x09, 0x53, 0x83, 0x00, 0x00, 0x00, 0xDF, 0xFE};
 static const unsigned int	string_initialization_short[9] = {0xFF, 0x09, 0x53, 0x03, 0x00, 0x00, 0x00, 0x5F, 0xFE};
+static const unsigned int	string_initialization_comptmode[5] = {0xFF, 0x05, 0x01, 0x06, 0xFE};
 
 static int		debug_pkt_data = 0, debug_pkt_hwinfo = 0, debug_pkt_raw = 0;
 
 static TYPE_FD_SER	serial_fd = ERROR_FD_SER;
 static unsigned char	chr;
 static size_t		datapacket_index = 0;
+static unsigned int	datapacketsize = 0;
 static bool		datapacketstart = false;
 static time_t		lastdp = 0;
 static unsigned int	checktime = 2000000;	/* 2 seconds */
@@ -371,10 +377,12 @@ static float calculate_efficiency(float vacoutrms, float vacinrms);
 static void parse_serial_options(void);
 static void close_serial_port(void);
 static TYPE_FD_SER openfd(const char *portarg, int requested_baudrate);
+static TYPE_FD_SER reconnect_ups_if_needed(void);
 #if 0
 static int write_serial(int fd, const char * dados, int size);
 #endif
 static int write_serial_int(TYPE_FD_SER fd, const unsigned int *data, size_t size);
+static bool send_initialization_packet(const unsigned int *data, size_t size, TYPE_FD_SER fd);
 
 static void print_pkt_hwinfo(pkt_hwinfo data);
 static void print_pkt_data(pkt_data data);
@@ -399,9 +407,8 @@ static int get_bit_in_position(void *ptr, size_t size, size_t bit_position, int
 	size_t	byte_index = bit_position / 8;
 	size_t	bit_index = bit_position % 8;
 
-	if (bit_position >= size * 8) {
+	if (bit_position >= size * 8)
 		return -3;	/* Invalid Position */
-	}
 
 	if (invertorder == 0)
 		retval = (byte_ptr[byte_index] >> (7 - bit_index)) & 1 ? 1 : 0;
@@ -411,7 +418,7 @@ static int get_bit_in_position(void *ptr, size_t size, size_t bit_position, int
 }
 
 static void print_pkt_hwinfo(pkt_hwinfo data) {
-	int	i = 0;
+	int	i = 0, retorno;
 
 	if (!debug_pkt_hwinfo)
 		return;
@@ -429,10 +436,10 @@ static void print_pkt_hwinfo(pkt_hwinfo data) {
 	upsdebugx(5, "Configuration Array: ");
 	upsdebugx(5, "-----");
 	for (i = 0; i < 5; i++) {
-		int	retorno = get_bit_in_position(&data.configuration, sizeof(data.configuration), i, 0);
+		retorno = get_bit_in_position(&data.configuration, sizeof(data.configuration), i, 0);
 		upsdebugx(5, "Binary value is %d", retorno);
 		upsdebugx(5, "%u ", data.configuration_array[i]);
-	}
+	}	/* end for */
 	upsdebugx(5, "-----");
 
 	upsdebugx(5, "OEM Mode: %s", data.c_oem_mode ? "true" : "false");
@@ -454,7 +461,7 @@ static void print_pkt_hwinfo(pkt_hwinfo data) {
 	for (i = 0; i < 6; i++) {
 		upsdebugx(5, "Binary value is %d", get_bit_in_position(&data.statusval, sizeof(data.statusval), i, 0));
 		upsdebugx(5, "status %d --> %u ", i, data.status[i]);
-	}
+	}	/* end for */
 	upsdebugx(5, "-----");
 
 	upsdebugx(5, "220V In: %s", data.s_220V_in ? "true" : "false");
@@ -527,7 +534,7 @@ static void print_pkt_data(pkt_data data) {
 	for (i = 0; i < 8; i++) {
 		upsdebugx(5, "Binary value is %d", get_bit_in_position(&data.statusval, sizeof(data.statusval), i, 0));
 		upsdebugx(5, "status %d --> %u ", i, data.status[i]);
-	}
+	}	/* end for */
 	upsdebugx(5, "-----");
 
 	upsdebugx(5, "Nominal Tension: %u", data.nominaltension);
@@ -563,8 +570,7 @@ static void parse_serial_options(void)
 	serial_data_bits = DEFAULT_SERIAL_DATA_BITS;
 	snprintf(serial_parity, sizeof(serial_parity), "%s", DEFAULT_SERIAL_PARITY);
 	serial_stop_bits = DEFAULT_SERIAL_STOP_BITS;
-	snprintf(serial_flow_control, sizeof(serial_flow_control), "%s",
-		DEFAULT_SERIAL_FLOW_CONTROL);
+	snprintf(serial_flow_control, sizeof(serial_flow_control), "%s", DEFAULT_SERIAL_FLOW_CONTROL);
 	serial_read_timeout_ms = DEFAULT_SERIAL_READ_TIMEOUT_MS;
 	serial_send_pace_us = DEFAULT_SERIAL_SEND_PACE_US;
 
@@ -577,26 +583,17 @@ static void parse_serial_options(void)
 		errno = 0;
 		endptr = NULL;
 		number = strtol(value, &endptr, 10);
-		if (errno != 0 || endptr == value || *endptr != '\0' || number <= 0) {
-			fatalx(EXIT_FAILURE,
-				"Invalid baud value '%s': expected a supported baud rate",
-				value);
-		}
+		if (errno != 0 || endptr == value || *endptr != '\0' || number <= 0)
+			fatalx(EXIT_FAILURE, "Invalid baud value '%s': expected a supported baud rate", value);
 
 		supported = 0;
-		for (i = 0; i < NUM_BAUD_RATES; i++) {
-			if (number == baud_rates[i].speed) {
+		for (i = 0; i < NUM_BAUD_RATES && !supported; i++)
+			if (number == baud_rates[i].speed)
 				supported = 1;
-				break;
-			}
-		}
-		if (!supported) {
-			fatalx(EXIT_FAILURE,
-				"Invalid baud value '%s': rate is not available in this build",
-				value);
-		}
+		if (!supported)
+			fatalx(EXIT_FAILURE, "Invalid baud value '%s': rate is not available in this build", value);
 		baudrate = (int)number;
-	}
+	}	/* end if */
 
 	value = getval("serial_data_bits");
 	if (value) {
@@ -604,54 +601,34 @@ static void parse_serial_options(void)
 		errno = 0;
 		endptr = NULL;
 		number = strtol(value, &endptr, 10);
-		if (errno != 0 || endptr == value || *endptr != '\0' ||
-			(number != 5 && number != 6 && number != 7 && number != 8)) {
-			fatalx(EXIT_FAILURE,
-				"Invalid serial_data_bits value '%s': expected 5, 6, 7 or 8",
-				value);
-		}
+		if (errno != 0 || endptr == value || *endptr != '\0' || (number != 5 && number != 6 && number != 7 && number != 8))
+			fatalx(EXIT_FAILURE, "Invalid serial_data_bits value '%s': expected 5, 6, 7 or 8", value);
 		serial_data_bits = (unsigned int)number;
-	}
+	}	/* end if */
 
 	value = getval("serial_parity");
 	if (value) {
-		if (strcasecmp(value, "none") != 0 &&
-			strcasecmp(value, "even") != 0 &&
-			strcasecmp(value, "odd") != 0) {
-			fatalx(EXIT_FAILURE,
-				"Invalid serial_parity value '%s': expected none, even or odd",
-				value);
-		}
+		if (strcasecmp(value, "none") != 0 && strcasecmp(value, "even") != 0 && strcasecmp(value, "odd") != 0)
+			fatalx(EXIT_FAILURE, "Invalid serial_parity value '%s': expected none, even or odd", value);
 		snprintf(serial_parity, sizeof(serial_parity), "%s", value);
-	}
+	}	/* end if */
 
 	value = getval("serial_stop_bits");
 	if (value) {
 		errno = 0;
 		endptr = NULL;
 		number = strtol(value, &endptr, 10);
-		if (errno != 0 || endptr == value || *endptr != '\0' ||
-			(number != 1 && number != 2)) {
-			fatalx(EXIT_FAILURE,
-				"Invalid serial_stop_bits value '%s': expected 1 or 2",
-				value);
-		}
+		if (errno != 0 || endptr == value || *endptr != '\0' || (number != 1 && number != 2))
+			fatalx(EXIT_FAILURE, "Invalid serial_stop_bits value '%s': expected 1 or 2", value);
 		serial_stop_bits = (unsigned int)number;
-	}
+	}	/* end if */
 
 	value = getval("serial_flow_control");
 	if (value) {
-		if (strcasecmp(value, "none") != 0 &&
-			strcasecmp(value, "hardware") != 0 &&
-			strcasecmp(value, "software") != 0 &&
-			strcasecmp(value, "both") != 0) {
-			fatalx(EXIT_FAILURE,
-				"Invalid serial_flow_control value '%s': expected "
-				"none, hardware, software or both",
-				value);
-		}
+		if (strcasecmp(value, "none") != 0 && strcasecmp(value, "hardware") != 0 && strcasecmp(value, "software") != 0 && strcasecmp(value, "both") != 0)
+			fatalx(EXIT_FAILURE, "Invalid serial_flow_control value '%s': expected none, hardware, software or both", value);
 		snprintf(serial_flow_control, sizeof(serial_flow_control), "%s", value);
-	}
+	}	/* end if */
 
 	value = getval("serial_read_timeout_ms");
 	if (value) {
@@ -659,14 +636,10 @@ static void parse_serial_options(void)
 		errno = 0;
 		endptr = NULL;
 		number = strtol(value, &endptr, 10);
-		if (errno != 0 || endptr == value || *endptr != '\0' ||
-			number < 0 || number > MAX_SERIAL_READ_TIMEOUT_MS) {
-			fatalx(EXIT_FAILURE,
-				"Invalid serial_read_timeout_ms value '%s': expected 0 to %d",
-				value, MAX_SERIAL_READ_TIMEOUT_MS);
-		}
+		if (errno != 0 || endptr == value || *endptr != '\0' || number < 0 || number > MAX_SERIAL_READ_TIMEOUT_MS)
+			fatalx(EXIT_FAILURE, "Invalid serial_read_timeout_ms value '%s': expected 0 to %d", value, MAX_SERIAL_READ_TIMEOUT_MS);
 		serial_read_timeout_ms = (unsigned int)number;
-	}
+	}	/* end if */
 
 	value = getval("serial_send_pace_us");
 	if (value) {
@@ -674,26 +647,20 @@ static void parse_serial_options(void)
 		errno = 0;
 		endptr = NULL;
 		number = strtol(value, &endptr, 10);
-		if (errno != 0 || endptr == value || *endptr != '\0' ||
-			number < 0 || number > MAX_SERIAL_SEND_PACE_US) {
-			fatalx(EXIT_FAILURE,
-				"Invalid serial_send_pace_us value '%s': expected 0 to %d",
-				value, MAX_SERIAL_SEND_PACE_US);
-		}
+		if (errno != 0 || endptr == value || *endptr != '\0' || number < 0 || number > MAX_SERIAL_SEND_PACE_US)
+			fatalx(EXIT_FAILURE, "Invalid serial_send_pace_us value '%s': expected 0 to %d", value, MAX_SERIAL_SEND_PACE_US);
 		serial_send_pace_us = (unsigned int)number;
-	}
+	}	/* end if */
 }
 
 static void close_serial_port(void)
 {
 	/* Use NUT's portable descriptor checks and always invalidate after closing. */
 	if (VALID_FD_SER(serial_fd)) {
-		if (ser_close(serial_fd, porta) != 0) {
-			upsdebug_with_errno(1, "%s: Error closing serial port %s",
-				__func__, porta);
-		}
+		if (ser_close(serial_fd, porta) != 0)
+			upsdebug_with_errno(1, "%s: Error closing serial port %s", __func__, porta);
 		serial_fd = ERROR_FD_SER;
-	}
+	}	/* end if */
 }
 
 static TYPE_FD_SER openfd(const char *portarg, int requested_baudrate)
@@ -704,21 +671,17 @@ static TYPE_FD_SER openfd(const char *portarg, int requested_baudrate)
 	size_t		i;
 
 	/* Translate the numeric ups.conf value to the matching termios constant. */
-	for (i = 0; i < NUM_BAUD_RATES; i++) {
+	for (i = 0; i < NUM_BAUD_RATES && rate == 0; i++) {
 		if (baud_rates[i].speed == requested_baudrate) {
 			rate = baud_rates[i].rate;
-			upsdebugx(1, "%s: Selected baud rate %d -- %s",
-				__func__, baud_rates[i].speed,
-				baud_rates[i].description);
-			break;
-		}
-	}
+			upsdebugx(1, "%s: Selected baud rate %d -- %s", __func__, baud_rates[i].speed, baud_rates[i].description);
+		}	/* end if */
+	}	/* end for */
 
 	if (rate == 0) {
-		upslogx(LOG_ERR, "%s: Unsupported baud rate %d",
-			__func__, requested_baudrate);
+		upslogx(LOG_ERR, "%s: Unsupported baud rate %d", __func__, requested_baudrate);
 		return ERROR_FD_SER;
-	}
+	}	/* end if */
 
 	/*
 	 * Establish NUT's standard raw serial baseline first, then customize only
@@ -728,32 +691,36 @@ static TYPE_FD_SER openfd(const char *portarg, int requested_baudrate)
 	if (INVALID_FD_SER(fd)) {
 		upsdebug_with_errno(1, "%s: Error opening %s", __func__, portarg);
 		return ERROR_FD_SER;
-	}
+	}	/* end if */
 
 	if (ser_set_speed_nf(fd, portarg, rate) != 0) {
-		upsdebug_with_errno(1, "%s: Error setting baud rate on %s",
-			__func__, portarg);
+		upsdebug_with_errno(1, "%s: Error setting baud rate on %s", __func__, portarg);
 		ser_close(fd, portarg);
 		return ERROR_FD_SER;
-	}
+	}	/* end if */
 
 	if (tcgetattr(fd, &tty) != 0) {
-		upsdebug_with_errno(1, "%s: Error reading serial settings from %s",
-			__func__, portarg);
+		upsdebug_with_errno(1, "%s: Error reading serial settings from %s", __func__, portarg);
 		ser_close(fd, portarg);
 		return ERROR_FD_SER;
-	}
+	}	/* end if */
 
 	/* Replace the baseline character size with the validated selection. */
 	tty.c_cflag &= ~CSIZE;
-	if (serial_data_bits == 5)
-		tty.c_cflag |= CS5;
-	else if (serial_data_bits == 6)
-		tty.c_cflag |= CS6;
-	else if (serial_data_bits == 7)
-		tty.c_cflag |= CS7;
-	else
-		tty.c_cflag |= CS8;
+	switch (serial_data_bits) {
+		case 5:
+			tty.c_cflag |= CS5;
+			break;
+		case 6:
+			tty.c_cflag |= CS6;
+			break;
+		case 7:
+			tty.c_cflag |= CS7;
+			break;
+		default:
+			tty.c_cflag |= CS8;
+			break;
+	}	/* end switch */
 
 	/*
 	 * Configure parity as a complete unit. Parity errors are ignored for
@@ -761,19 +728,20 @@ static TYPE_FD_SER openfd(const char *portarg, int requested_baudrate)
 	 */
 	tty.c_cflag &= ~(PARENB | PARODD);
 	tty.c_iflag &= ~INPCK;
-	if (strcasecmp(serial_parity, "none") == 0) {
+	if (strcasecmp(serial_parity, "none") == 0)
 		tty.c_iflag |= IGNPAR;
-	}
-	else if (strcasecmp(serial_parity, "even") == 0) {
-		tty.c_iflag &= ~IGNPAR;
-		tty.c_cflag |= PARENB;
-		tty.c_iflag |= INPCK;
-	}
 	else {
-		tty.c_iflag &= ~IGNPAR;
-		tty.c_cflag |= PARENB | PARODD;
-		tty.c_iflag |= INPCK;
-	}
+		if (strcasecmp(serial_parity, "even") == 0) {
+			tty.c_iflag &= ~IGNPAR;
+			tty.c_cflag |= PARENB;
+			tty.c_iflag |= INPCK;
+		}	/* end if */
+		else {
+			tty.c_iflag &= ~IGNPAR;
+			tty.c_cflag |= PARENB | PARODD;
+			tty.c_iflag |= INPCK;
+		}	/* end else */
+	}	/* end else */
 
 	/* CSTOPB clear means one stop bit; set means two stop bits. */
 	if (serial_stop_bits == 2)
@@ -791,40 +759,37 @@ static TYPE_FD_SER openfd(const char *portarg, int requested_baudrate)
 
 	if (strcasecmp(serial_flow_control, "none") == 0) {
 		/* Hardware and software flow control remain disabled. */
-	}
-	else if (strcasecmp(serial_flow_control, "hardware") == 0) {
-		tty.c_cflag |= CRTSCTS;
-	}
-	else if (strcasecmp(serial_flow_control, "software") == 0) {
-		tty.c_iflag |= IXON | IXOFF;
-	}
-	else if (strcasecmp(serial_flow_control, "both") == 0) {
-		tty.c_cflag |= CRTSCTS;
-		tty.c_iflag |= IXON | IXOFF;
-	}
+	}	/* end if */
+	else {
+		if (strcasecmp(serial_flow_control, "hardware") == 0)
+			tty.c_cflag |= CRTSCTS;
+		else {
+			if (strcasecmp(serial_flow_control, "software") == 0)
+				tty.c_iflag |= IXON | IXOFF;
+			else {
+				if (strcasecmp(serial_flow_control, "both") == 0) {
+					tty.c_cflag |= CRTSCTS;
+					tty.c_iflag |= IXON | IXOFF;
+				}	/* end if */
+			}	/* end else */
+		}	/* end else */
+	}	/* end else */
 
 	/* Apply the four conventional settings together. */
 	if (tcsetattr(fd, TCSANOW, &tty) != 0) {
-		upsdebug_with_errno(1, "%s: Error applying serial settings to %s",
-			__func__, portarg);
+		upsdebug_with_errno(1, "%s: Error applying serial settings to %s", __func__, portarg);
 		ser_close(fd, portarg);
 		return ERROR_FD_SER;
-	}
+	}	/* end if */
 
 	/* Discard bytes queued under any previous port configuration. */
 	if (ser_flush_io(fd) != 0) {
-		upsdebug_with_errno(1, "%s: Error flushing serial port %s",
-			__func__, portarg);
+		upsdebug_with_errno(1, "%s: Error flushing serial port %s", __func__, portarg);
 		ser_close(fd, portarg);
 		return ERROR_FD_SER;
-	}
+	}	/* end if */
 
-	upsdebugx(1, "%s: Serial settings: %d baud, %u data bits, %s parity, "
-		"%u stop bit(s), %s flow control, read timeout %u ms, "
-		"send pace %u us",
-		__func__, requested_baudrate, serial_data_bits, serial_parity,
-		serial_stop_bits, serial_flow_control,
-		serial_read_timeout_ms, serial_send_pace_us);
+	upsdebugx(1, "%s: Serial settings: %d baud, %u data bits, %s parity, %u stop bit(s), %s flow control, read timeout %u ms, send pace %u us", __func__, requested_baudrate, serial_data_bits, serial_parity, serial_stop_bits, serial_flow_control, serial_read_timeout_ms, serial_send_pace_us);
 
 	return fd;
 }
@@ -832,9 +797,8 @@ static TYPE_FD_SER openfd(const char *portarg, int requested_baudrate)
 static unsigned char calculate_checksum(unsigned char *pacote, int inicio, int fim) {
 	int	soma = 0, i = 0;
 
-	for (i = inicio; i <= fim; i++) {
+	for (i = inicio; i <= fim; i++)
 		soma += pacote[i];
-	}
 	return (soma & 0xFF);
 }
 
@@ -848,10 +812,9 @@ static void pdatapacket(unsigned char *datapkt, size_t size) {
 		/* FIXME: convert to upsdebug_hex()? */
 		upsdebugx(1, "%s: logging received data packet bytes at debug verbosity 5 or more", __func__);
 
-		for (i = 0; i < size; i++) {
+		for (i = 0; i < size; i++)
 			upsdebugx(5, "\tPosition %" PRIuSIZE " -- 0x%02X -- Decimal %d -- Char %c", i, datapkt[i], datapkt[i], datapkt[i]);
-		}
-	}
+	}	/* end if */
 }
 
 static float createfloat(int integer, int decimal) {
@@ -862,12 +825,10 @@ static float createfloat(int integer, int decimal) {
 
 static unsigned int get_vbat(void) {
 	char	*v = getval("vbat");
-	if (v) {
+	if (v)
 		return atoi(v);
-	}
-	else {
+	else
 		return DEFAULTBATV;
-	}
 }
 
 static pkt_data mount_datapacket(unsigned char *datapkt, size_t size, double tempodecorrido, pkt_hwinfo pkt_upsinfo)  {
@@ -999,7 +960,7 @@ static pkt_data mount_datapacket(unsigned char *datapkt, size_t size, double tem
 	if (debug_pkt_data) {
 		pdatapacket(datapkt, size);
 		print_pkt_data(pktdata);
-	}
+	}	/* end if */
 
 	return pktdata;
 }
@@ -1114,7 +1075,7 @@ static pkt_hwinfo mount_hwinfo(unsigned char *datapkt, size_t size) {
 	else {
 		pkthwinfo.checksum = datapkt[16];
 		checksum = calculate_checksum(datapkt, 1, 15);
-	}
+	}	/* end else */
 	pkthwinfo.checksum_calc = checksum;
 	if (pkthwinfo.checksum == checksum)
 		pkthwinfo.checksum_ok = true;
@@ -1122,21 +1083,23 @@ static pkt_hwinfo mount_hwinfo(unsigned char *datapkt, size_t size) {
 	if (debug_pkt_hwinfo) {
 		pdatapacket(datapkt, size);
 		print_pkt_hwinfo(pkthwinfo);
-	}
+	}	/* end if */
 
 	return pkthwinfo;
 }
 
 #if 0
 static int write_serial(int fd, const char *dados, size_t size) {
+	ssize_t	bytes_written;
+
 	if (fd > 0) {
-		ssize_t	bytes_written = write(fd, dados, size);
+		bytes_written = write(fd, dados, size);
 		if (bytes_written < 0)
 			return -1;
 		if (tcdrain(fd) != 0)
 			return -2;
 		return size;
-	}
+	}	/* end if */
 	else
 		return fd;
 }
@@ -1164,8 +1127,7 @@ static int write_serial_int(TYPE_FD_SER fd, const unsigned int *data, size_t siz
 	if (serial_send_pace_us == 0)
 		sent = ser_send_buf(fd, message, size);
 	else
-		sent = ser_send_buf_pace(fd,
-			(useconds_t)serial_send_pace_us, message, size);
+		sent = ser_send_buf_pace(fd, (useconds_t)serial_send_pace_us, message, size);
 
 	free(message);
 
@@ -1185,663 +1147,158 @@ static char * strtolow(char* s) {
 }
 #endif
 
-static upsinfo getupsinfo(unsigned int upscode) {
-	upsinfo	data;
-	switch (upscode) {
-		case 1:
-			data.upscode = 1;
-			strncpy(data.upsdesc, "NHS COMPACT PLUS", sizeof(data.upsdesc));
-			data.VA = 1000;
-			break;
-
-		case 2:
-			data.upscode = 2;
-			strncpy(data.upsdesc, "NHS COMPACT PLUS SENOIDAL", sizeof(data.upsdesc));
-			data.VA = 1000;
-			break;
-
-		case 3:
-			data.upscode = 3;
-			strncpy(data.upsdesc, "NHS COMPACT PLUS RACK", sizeof(data.upsdesc));
-			data.VA = 1000;
-			break;
-
-		case 4:
-			data.upscode = 4;
-			strncpy(data.upsdesc, "NHS PREMIUM PDV", sizeof(data.upsdesc));
-			data.VA = 1500;
-			break;
-
-		case 5:
-			data.upscode = 5;
-			strncpy(data.upsdesc, "NHS PREMIUM PDV SENOIDAL", sizeof(data.upsdesc));
-			data.VA = 1500;
-			break;
-
-		case 6:
-			data.upscode = 6;
-			strncpy(data.upsdesc, "NHS PREMIUM 1500VA", sizeof(data.upsdesc));
-			data.VA = 1500;
-			break;
-
-		case 7:
-			data.upscode = 7;
-			strncpy(data.upsdesc, "NHS PREMIUM 2200VA", sizeof(data.upsdesc));
-			data.VA = 2200;
-			break;
-
-		case 8:
-			data.upscode = 8;
-			strncpy(data.upsdesc, "NHS PREMIUM SENOIDAL", sizeof(data.upsdesc));
-			data.VA = 1500;
-			break;
-
-		case 9:
-			data.upscode = 9;
-			strncpy(data.upsdesc, "NHS LASER 2600VA", sizeof(data.upsdesc));
-			data.VA = 2600;
-			break;
-
-		case 10:
-			data.upscode = 10;
-			strncpy(data.upsdesc, "NHS LASER 3300VA", sizeof(data.upsdesc));
-			data.VA = 3300;
-			break;
-
-		case 11:
-			data.upscode = 11;
-			strncpy(data.upsdesc, "NHS LASER 2600VA ISOLADOR", sizeof(data.upsdesc));
-			data.VA = 2600;
-			break;
-
-		case 12:
-			data.upscode = 12;
-			strncpy(data.upsdesc, "NHS LASER SENOIDAL", sizeof(data.upsdesc));
-			data.VA = 2600;
-			break;
-
-		case 13:
-			data.upscode = 13;
-			strncpy(data.upsdesc, "NHS LASER ON-LINE", sizeof(data.upsdesc));
-			data.VA = 2600;
-			break;
-
-		case 15:
-			data.upscode = 15;
-			strncpy(data.upsdesc, "NHS COMPACT PLUS 2003", sizeof(data.upsdesc));
-			data.VA = 1000;
-			break;
-
-		case 16:
-			data.upscode = 16;
-			strncpy(data.upsdesc, "COMPACT PLUS SENOIDAL 2003", sizeof(data.upsdesc));
-			data.VA = 1000;
-			break;
-
-		case 17:
-			data.upscode = 17;
-			strncpy(data.upsdesc, "COMPACT PLUS RACK 2003", sizeof(data.upsdesc));
-			data.VA = 1000;
-			break;
-
-		case 18:
-			data.upscode = 18;
-			strncpy(data.upsdesc, "PREMIUM PDV 2003", sizeof(data.upsdesc));
-			data.VA = 1500;
-			break;
-
-		case 19:
-			data.upscode = 19;
-			strncpy(data.upsdesc, "PREMIUM PDV SENOIDAL 2003", sizeof(data.upsdesc));
-			data.VA = 1500;
-			break;
-
-		case 20:
-			data.upscode = 20;
-			strncpy(data.upsdesc, "PREMIUM 1500VA 2003", sizeof(data.upsdesc));
-			data.VA = 1500;
-			break;
-
-		case 21:
-			data.upscode = 21;
-			strncpy(data.upsdesc, "PREMIUM 2200VA 2003", sizeof(data.upsdesc));
-			data.VA = 2200;
-			break;
-
-		case 22:
-			data.upscode = 22;
-			strncpy(data.upsdesc, "PREMIUM SENOIDAL 2003", sizeof(data.upsdesc));
-			data.VA = 1500;
-			break;
-
-		case 23:
-			data.upscode = 23;
-			strncpy(data.upsdesc, "LASER 2600VA 2003", sizeof(data.upsdesc));
-			data.VA = 2600;
-			break;
-
-		case 24:
-			data.upscode = 24;
-			strncpy(data.upsdesc, "LASER 3300VA 2003", sizeof(data.upsdesc));
-			data.VA = 3300;
-			break;
-
-		case 25:
-			data.upscode = 25;
-			strncpy(data.upsdesc, "LASER 2600VA ISOLADOR 2003", sizeof(data.upsdesc));
-			data.VA = 2600;
-			break;
-
-		case 26:
-			data.upscode = 26;
-			strncpy(data.upsdesc, "LASER SENOIDAL 2003", sizeof(data.upsdesc));
-			data.VA = 2600;
-			break;
-
-		case 27:
-			data.upscode = 27;
-			strncpy(data.upsdesc, "PDV ONLINE 2003", sizeof(data.upsdesc));
-			data.VA = 1500;
-			break;
-
-		case 28:
-			data.upscode = 28;
-			strncpy(data.upsdesc, "LASER ONLINE 2003", sizeof(data.upsdesc));
-			data.VA = 3300;
-			break;
-
-		case 29:
-			data.upscode = 29;
-			strncpy(data.upsdesc, "EXPERT ONLINE 2003", sizeof(data.upsdesc));
-			data.VA = 5000;
-			break;
-
-		case 30:
-			data.upscode = 30;
-			strncpy(data.upsdesc, "MINI 2", sizeof(data.upsdesc));
-			data.VA = 500;
-			break;
-
-		case 31:
-			data.upscode = 31;
-			strncpy(data.upsdesc, "COMPACT PLUS 2", sizeof(data.upsdesc));
-			data.VA = 1000;
-			break;
-
-		case 32:
-			data.upscode = 32;
-			strncpy(data.upsdesc, "LASER ON-LINE", sizeof(data.upsdesc));
-			data.VA = 2600;
-			break;
-
-		case 33:
-			data.upscode = 33;
-			strncpy(data.upsdesc, "PDV SENOIDAL 1500VA", sizeof(data.upsdesc));
-			data.VA = 1500;
-			break;
-
-		case 34:
-			data.upscode = 34;
-			strncpy(data.upsdesc, "PDV SENOIDAL 1000VA", sizeof(data.upsdesc));
-			data.VA = 1000;
-			break;
-
-		case 36:
-			data.upscode = 36;
-			strncpy(data.upsdesc, "LASER ONLINE 3750VA", sizeof(data.upsdesc));
-			data.VA = 3750;
-			break;
-
-		case 37:
-			data.upscode = 37;
-			strncpy(data.upsdesc, "LASER ONLINE 5000VA", sizeof(data.upsdesc));
-			data.VA = 5000;
-			break;
-
-		case 38:
-			data.upscode = 38;
-			strncpy(data.upsdesc, "PREMIUM SENOIDAL 2000VA", sizeof(data.upsdesc));
-			data.VA = 2000;
-			break;
-
-		case 39:
-			data.upscode = 39;
-			strncpy(data.upsdesc, "LASER SENOIDAL 3500VA", sizeof(data.upsdesc));
-			data.VA = 3500;
-			break;
-
-		case 40:
-			data.upscode = 40;
-			strncpy(data.upsdesc, "PREMIUM PDV 1200VA", sizeof(data.upsdesc));
-			data.VA = 1200;
-			break;
-
-		case 41:
-			data.upscode = 41;
-			strncpy(data.upsdesc, "PREMIUM 1500VA", sizeof(data.upsdesc));
-			data.VA = 1500;
-			break;
-
-		case 42:
-			data.upscode = 42;
-			strncpy(data.upsdesc, "PREMIUM 2200VA", sizeof(data.upsdesc));
-			data.VA = 2200;
-			break;
-
-		case 43:
-			data.upscode = 43;
-			strncpy(data.upsdesc, "LASER 2600VA", sizeof(data.upsdesc));
-			data.VA = 2600;
-			break;
-
-		case 44:
-			data.upscode = 44;
-			strncpy(data.upsdesc, "LASER 3300VA", sizeof(data.upsdesc));
-			data.VA = 3300;
-			break;
-
-		case 45:
-			data.upscode = 45;
-			strncpy(data.upsdesc, "COMPACT PLUS SENOIDAL 700VA", sizeof(data.upsdesc));
-			data.VA = 700;
-			break;
-
-		case 46:
-			data.upscode = 46;
-			strncpy(data.upsdesc, "PREMIUM ONLINE 2000VA", sizeof(data.upsdesc));
-			data.VA = 2000;
-			break;
-
-		case 47:
-			data.upscode = 47;
-			strncpy(data.upsdesc, "EXPERT ONLINE 10000VA", sizeof(data.upsdesc));
-			data.VA = 10000;
-			break;
-
-		case 48:
-			data.upscode = 48;
-			strncpy(data.upsdesc, "LASER SENOIDAL 4200VA", sizeof(data.upsdesc));
-			data.VA = 4200;
-			break;
-
-		case 49:
-			data.upscode = 49;
-			strncpy(data.upsdesc, "NHS COMPACT PLUS EXTENDIDO 1500VA", sizeof(data.upsdesc));
-			data.VA = 1500;
-			break;
-
-		case 50:
-			data.upscode = 50;
-			strncpy(data.upsdesc, "LASER ONLINE 6000VA", sizeof(data.upsdesc));
-			data.VA = 6000;
-			break;
-
-		case 51:
-			data.upscode = 51;
-			strncpy(data.upsdesc, "LASER EXT 3300VA", sizeof(data.upsdesc));
-			data.VA = 3300;
-			break;
-
-		case 52:
-			data.upscode = 52;
-			strncpy(data.upsdesc, "NHS COMPACT PLUS 1200VA", sizeof(data.upsdesc));
-			data.VA = 1200;
-			break;
-
-		case 53:
-			data.upscode = 53;
-			strncpy(data.upsdesc, "LASER SENOIDAL 3000VA GII", sizeof(data.upsdesc));
-			data.VA = 3000;
-			break;
-
-		case 54:
-			data.upscode = 54;
-			strncpy(data.upsdesc, "LASER SENOIDAL 3500VA GII", sizeof(data.upsdesc));
-			data.VA = 3500;
-			break;
-
-		case 55:
-			data.upscode = 55;
-			strncpy(data.upsdesc, "LASER SENOIDAL 4200VA GII", sizeof(data.upsdesc));
-			data.VA = 4200;
-			break;
-
-		case 56:
-			data.upscode = 56;
-			strncpy(data.upsdesc, "LASER ONLINE 3000VA", sizeof(data.upsdesc));
-			data.VA = 3000;
-			break;
-
-		case 57:
-			data.upscode = 57;
-			strncpy(data.upsdesc, "LASER ONLINE 3750VA", sizeof(data.upsdesc));
-			data.VA = 3750;
-			break;
-
-		case 58:
-			data.upscode = 58;
-			strncpy(data.upsdesc, "LASER ONLINE 5000VA", sizeof(data.upsdesc));
-			data.VA = 5000;
-			break;
-
-		case 59:
-			data.upscode = 59;
-			strncpy(data.upsdesc, "LASER ONLINE 6000VA", sizeof(data.upsdesc));
-			data.VA = 6000;
-			break;
-
-		case 60:
-			data.upscode = 60;
-			strncpy(data.upsdesc, "PREMIUM ONLINE 2000VA", sizeof(data.upsdesc));
-			data.VA = 2000;
-			break;
-
-		case 61:
-			data.upscode = 61;
-			strncpy(data.upsdesc, "PREMIUM ONLINE 1500VA", sizeof(data.upsdesc));
-			data.VA = 1500;
-			break;
-
-		case 62:
-			data.upscode = 62;
-			strncpy(data.upsdesc, "PREMIUM ONLINE 1200VA", sizeof(data.upsdesc));
-			data.VA = 1200;
-			break;
-
-		case 63:
-			data.upscode = 63;
-			strncpy(data.upsdesc, "COMPACT PLUS II MAX 1400VA", sizeof(data.upsdesc));
-			data.VA = 1400;
-			break;
-
-		case 64:
-			data.upscode = 64;
-			strncpy(data.upsdesc, "PREMIUM PDV MAX 2200VA", sizeof(data.upsdesc));
-			data.VA = 2200;
-			break;
-
-		case 65:
-			data.upscode = 65;
-			strncpy(data.upsdesc, "PREMIUM PDV 3000VA", sizeof(data.upsdesc));
-			data.VA = 3000;
-			break;
-
-		case 66:
-			data.upscode = 66;
-			strncpy(data.upsdesc, "PREMIUM SENOIDAL 2200VA GII", sizeof(data.upsdesc));
-			data.VA = 2200;
-			break;
-
-		case 67:
-			data.upscode = 67;
-			strncpy(data.upsdesc, "LASER PRIME SENOIDAL 3200VA GII", sizeof(data.upsdesc));
-			data.VA = 3200;
-			break;
-
-		case 68:
-			data.upscode = 68;
-			strncpy(data.upsdesc, "PREMIUM RACK ONLINE 3000VA", sizeof(data.upsdesc));
-			data.VA = 3000;
-			break;
-
-		case 69:
-			data.upscode = 69;
-			strncpy(data.upsdesc, "PREMIUM ONLINE 3000VA", sizeof(data.upsdesc));
-			data.VA = 3000;
-			break;
-
-		case 70:
-			data.upscode = 70;
-			strncpy(data.upsdesc, "LASER ONLINE 4000VA", sizeof(data.upsdesc));
-			data.VA = 4000;
-			break;
-
-		case 71:
-			data.upscode = 71;
-			strncpy(data.upsdesc, "LASER ONLINE 7500VA", sizeof(data.upsdesc));
-			data.VA = 7500;
-			break;
-
-		case 72:
-			data.upscode = 72;
-			strncpy(data.upsdesc, "LASER ONLINE BIFASICO 5000VA", sizeof(data.upsdesc));
-			data.VA = 5000;
-			break;
-
-		case 73:
-			data.upscode = 73;
-			strncpy(data.upsdesc, "LASER ONLINE BIFASICO 6000VA", sizeof(data.upsdesc));
-			data.VA = 6000;
-			break;
-
-		case 74:
-			data.upscode = 74;
-			strncpy(data.upsdesc, "LASER ONLINE BIFASICO 7500VA", sizeof(data.upsdesc));
-			data.VA = 7500;
-			break;
-
-		case 75:
-			data.upscode = 75;
-			strncpy(data.upsdesc, "NHS MINI ST", sizeof(data.upsdesc));
-			data.VA = 500;
-			break;
-
-		case 76:
-			data.upscode = 76;
-			strncpy(data.upsdesc, "NHS MINI 120", sizeof(data.upsdesc));
-			data.VA = 120;
-			break;
-
-		case 77:
-			data.upscode = 77;
-			strncpy(data.upsdesc, "NHS MINI BIVOLT", sizeof(data.upsdesc));
-			data.VA = 500;
-			break;
-
-		case 78:
-			data.upscode = 78;
-			strncpy(data.upsdesc, "PDV 600", sizeof(data.upsdesc));
-			data.VA = 600;
-			break;
-
-		case 79:
-			data.upscode = 79;
-			strncpy(data.upsdesc, "NHS MINI MAX", sizeof(data.upsdesc));
-			data.VA = 500;
-			break;
-
-		case 80:
-			data.upscode = 80;
-			strncpy(data.upsdesc, "NHS MINI EXT", sizeof(data.upsdesc));
-			data.VA = 500;
-			break;
-
-		case 81:
-			data.upscode = 81;
-			strncpy(data.upsdesc, "NHS AUTONOMY PDV 4T", sizeof(data.upsdesc));
-			data.VA = 4000;
-			break;
-
-		case 82:
-			data.upscode = 82;
-			strncpy(data.upsdesc, "NHS AUTONOMY PDV 8T", sizeof(data.upsdesc));
-			data.VA = 8000;
-			break;
-
-		case 83:
-			data.upscode = 83;
-			strncpy(data.upsdesc, "NHS COMPACT PLUS RACK 1200VA", sizeof(data.upsdesc));
-			data.VA = 1200;
-			break;
-
-		case 84:
-			data.upscode = 84;
-			strncpy(data.upsdesc, "PDV SENOIDAL ISOLADOR 1500VA", sizeof(data.upsdesc));
-			data.VA = 1500;
-			break;
-
-		case 85:
-			data.upscode = 85;
-			strncpy(data.upsdesc, "NHS PDV RACK 1500VA", sizeof(data.upsdesc));
-			data.VA = 1500;
-			break;
-
-		case 86:
-			data.upscode = 86;
-			strncpy(data.upsdesc, "NHS PDV 1400VA S GII", sizeof(data.upsdesc));
-			data.VA = 1400;
-			break;
-
-		case 87:
-			data.upscode = 87;
-			strncpy(data.upsdesc, "PDV SENOIDAL ISOLADOR 1500VA", sizeof(data.upsdesc));
-			data.VA = 1500;
-			break;
-
-		case 88:
-			data.upscode = 88;
-			strncpy(data.upsdesc, "LASER PRIME SENOIDAL ISOLADOR 2000VA", sizeof(data.upsdesc));
-			data.VA = 2000;
-			break;
-
-		case 89:
-			data.upscode = 89;
-			strncpy(data.upsdesc, "PREMIUM SENOIDAL 2400VA GII", sizeof(data.upsdesc));
-			data.VA = 2400;
-			break;
-
-		case 90:
-			data.upscode = 90;
-			strncpy(data.upsdesc, "NHS PDV 1400VA S 8T GII", sizeof(data.upsdesc));
-			data.VA = 1400;
-			break;
-
-		case 91:
-			data.upscode = 91;
-			strncpy(data.upsdesc, "PREMIUM ONLINE 2000VA", sizeof(data.upsdesc));
-			data.VA = 2000;
-			break;
-
-		case 92:
-			data.upscode = 92;
-			strncpy(data.upsdesc, "LASER PRIME ONLINE 2200VA", sizeof(data.upsdesc));
-			data.VA = 2200;
-			break;
-
-		case 93:
-			data.upscode = 93;
-			strncpy(data.upsdesc, "PREMIUM RACK ONLINE 2200VA", sizeof(data.upsdesc));
-			data.VA = 2200;
-			break;
-
-		case 94:
-			data.upscode = 94;
-			strncpy(data.upsdesc, "PREMIUM SENOIDAL 2400VA GII", sizeof(data.upsdesc));
-			data.VA = 2400;
-			break;
-
-		case 95:
-			data.upscode = 95;
-			strncpy(data.upsdesc, "LASER ONLINE 10000VA", sizeof(data.upsdesc));
-			data.VA = 10000;
-			break;
-
-		case 96:
-			data.upscode = 96;
-			strncpy(data.upsdesc, "LASER ONLINE BIFASICO 10000VA", sizeof(data.upsdesc));
-			data.VA = 10000;
-			break;
-
-		case 97:
-			data.upscode = 97;
-			strncpy(data.upsdesc, "LASER SENOIDAL 3300VA GII", sizeof(data.upsdesc));
-			data.VA = 3300;
-			break;
-
-		case 98:
-			data.upscode = 98;
-			strncpy(data.upsdesc, "LASER SENOIDAL 2600VA GII", sizeof(data.upsdesc));
-			data.VA = 2600;
-			break;
-
-		case 99:
-			data.upscode = 99;
-			strncpy(data.upsdesc, "PREMIUM SENOIDAL 3000VA GII", sizeof(data.upsdesc));
-			data.VA = 3000;
-			break;
-
-		case 100:
-			data.upscode = 100;
-			strncpy(data.upsdesc, "PREMIUM SENOIDAL 2200VA GII", sizeof(data.upsdesc));
-			data.VA = 2200;
-			break;
-
-		case 101:
-			data.upscode = 101;
-			strncpy(data.upsdesc, "LASER ONLINE BIFASICO 4000VA", sizeof(data.upsdesc));
-			data.VA = 4000;
-			break;
-
-		case 102:
-			data.upscode = 102;
-			strncpy(data.upsdesc, "LASER ONLINE 12000VA", sizeof(data.upsdesc));
-			data.VA = 12000;
-			break;
-
-		case 103:
-			data.upscode = 103;
-			strncpy(data.upsdesc, "LASER ONLINE 8000VA", sizeof(data.upsdesc));
-			data.VA = 8000;
-			break;
-
-		case 104:
-			data.upscode = 104;
-			strncpy(data.upsdesc, "PDV SENOIDAL ISOLADOR 1000VA", sizeof(data.upsdesc));
-			data.VA = 1000;
-			break;
-
-		case 105:
-			data.upscode = 105;
-			strncpy(data.upsdesc, "MINI SENOIDAL 500VA", sizeof(data.upsdesc));
-			data.VA = 500;
-			break;
+/*
+ * Keep model metadata in an indexed table instead of a long switch to improve
+ * visualization of protocol codes, descriptions and nominal VA values while
+ * preserving direct lookup by the model code reported by the UPS.
+ */
+/*
+ * Initialize behavior metadata explicitly for every known model. Keeping the
+ * defaults beside the model data documents the resolved behavior and prevents
+ * strict builds from treating omitted structure fields as compilation errors.
+ */
+#define UPS_INFO_ENTRY(code, description, nominal_va) \
+	[code] = { code, description, nominal_va, 3, 1 }
+
+static const upsinfo ups_info_table[114] = {
+	UPS_INFO_ENTRY(1, "NHS COMPACT PLUS", 1000),
+	UPS_INFO_ENTRY(2, "NHS COMPACT PLUS SENOIDAL", 1000),
+	UPS_INFO_ENTRY(3, "NHS COMPACT PLUS RACK", 1000),
+	UPS_INFO_ENTRY(4, "NHS PREMIUM PDV", 1500),
+	UPS_INFO_ENTRY(5, "NHS PREMIUM PDV SENOIDAL", 1500),
+	UPS_INFO_ENTRY(6, "NHS PREMIUM 1500VA", 1500),
+	UPS_INFO_ENTRY(7, "NHS PREMIUM 2200VA", 2200),
+	UPS_INFO_ENTRY(8, "NHS PREMIUM SENOIDAL", 1500),
+	UPS_INFO_ENTRY(9, "NHS LASER 2600VA", 2600),
+	UPS_INFO_ENTRY(10, "NHS LASER 3300VA", 3300),
+	UPS_INFO_ENTRY(11, "NHS LASER 2600VA ISOLADOR", 2600),
+	UPS_INFO_ENTRY(12, "NHS LASER SENOIDAL", 2600),
+	UPS_INFO_ENTRY(13, "NHS LASER ON-LINE", 2600),
+	UPS_INFO_ENTRY(15, "NHS COMPACT PLUS 2003", 1000),
+	UPS_INFO_ENTRY(16, "COMPACT PLUS SENOIDAL 2003", 1000),
+	UPS_INFO_ENTRY(17, "COMPACT PLUS RACK 2003", 1000),
+	UPS_INFO_ENTRY(18, "PREMIUM PDV 2003", 1500),
+	UPS_INFO_ENTRY(19, "PREMIUM PDV SENOIDAL 2003", 1500),
+	UPS_INFO_ENTRY(20, "PREMIUM 1500VA 2003", 1500),
+	UPS_INFO_ENTRY(21, "PREMIUM 2200VA 2003", 2200),
+	UPS_INFO_ENTRY(22, "PREMIUM SENOIDAL 2003", 1500),
+	UPS_INFO_ENTRY(23, "LASER 2600VA 2003", 2600),
+	UPS_INFO_ENTRY(24, "LASER 3300VA 2003", 3300),
+	UPS_INFO_ENTRY(25, "LASER 2600VA ISOLADOR 2003", 2600),
+	UPS_INFO_ENTRY(26, "LASER SENOIDAL 2003", 2600),
+	UPS_INFO_ENTRY(27, "PDV ONLINE 2003", 1500),
+	UPS_INFO_ENTRY(28, "LASER ONLINE 2003", 3300),
+	UPS_INFO_ENTRY(29, "EXPERT ONLINE 2003", 5000),
+	UPS_INFO_ENTRY(30, "MINI 2", 500),
+	UPS_INFO_ENTRY(31, "COMPACT PLUS 2", 1000),
+	UPS_INFO_ENTRY(32, "LASER ON-LINE", 2600),
+	UPS_INFO_ENTRY(33, "PDV SENOIDAL 1500VA", 1500),
+	UPS_INFO_ENTRY(34, "PDV SENOIDAL 1000VA", 1000),
+	UPS_INFO_ENTRY(36, "LASER ONLINE 3750VA", 3750),
+	UPS_INFO_ENTRY(37, "LASER ONLINE 5000VA", 5000),
+	UPS_INFO_ENTRY(38, "PREMIUM SENOIDAL 2000VA", 2000),
+	UPS_INFO_ENTRY(39, "LASER SENOIDAL 3500VA", 3500),
+	UPS_INFO_ENTRY(40, "PREMIUM PDV 1200VA", 1200),
+	UPS_INFO_ENTRY(41, "PREMIUM 1500VA", 1500),
+	UPS_INFO_ENTRY(42, "PREMIUM 2200VA", 2200),
+	UPS_INFO_ENTRY(43, "LASER 2600VA", 2600),
+	UPS_INFO_ENTRY(44, "LASER 3300VA", 3300),
+	UPS_INFO_ENTRY(45, "COMPACT PLUS SENOIDAL 700VA", 700),
+	UPS_INFO_ENTRY(46, "PREMIUM ONLINE 2000VA", 2000),
+	UPS_INFO_ENTRY(47, "EXPERT ONLINE 10000VA", 10000),
+	UPS_INFO_ENTRY(48, "LASER SENOIDAL 4200VA", 4200),
+	UPS_INFO_ENTRY(49, "NHS COMPACT PLUS EXTENDIDO 1500VA", 1500),
+	UPS_INFO_ENTRY(50, "LASER ONLINE 6000VA", 6000),
+	UPS_INFO_ENTRY(51, "LASER EXT 3300VA", 3300),
+	UPS_INFO_ENTRY(52, "NHS COMPACT PLUS 1200VA", 1200),
+	UPS_INFO_ENTRY(53, "LASER SENOIDAL 3000VA GII", 3000),
+	UPS_INFO_ENTRY(54, "LASER SENOIDAL 3500VA GII", 3500),
+	UPS_INFO_ENTRY(55, "LASER SENOIDAL 4200VA GII", 4200),
+	UPS_INFO_ENTRY(56, "LASER ONLINE 3000VA", 3000),
+	UPS_INFO_ENTRY(57, "LASER ONLINE 3750VA", 3750),
+	UPS_INFO_ENTRY(58, "LASER ONLINE 5000VA", 5000),
+	UPS_INFO_ENTRY(59, "LASER ONLINE 6000VA", 6000),
+	UPS_INFO_ENTRY(60, "PREMIUM ONLINE 2000VA", 2000),
+	UPS_INFO_ENTRY(61, "PREMIUM ONLINE 1500VA", 1500),
+	UPS_INFO_ENTRY(62, "PREMIUM ONLINE 1200VA", 1200),
+	UPS_INFO_ENTRY(63, "COMPACT PLUS II MAX 1400VA", 1400),
+	UPS_INFO_ENTRY(64, "PREMIUM PDV MAX 2200VA", 2200),
+	UPS_INFO_ENTRY(65, "PREMIUM PDV 3000VA", 3000),
+	UPS_INFO_ENTRY(66, "PREMIUM SENOIDAL 2200VA GII", 2200),
+	UPS_INFO_ENTRY(67, "LASER PRIME SENOIDAL 3200VA GII", 3200),
+	UPS_INFO_ENTRY(68, "PREMIUM RACK ONLINE 3000VA", 3000),
+	UPS_INFO_ENTRY(69, "PREMIUM ONLINE 3000VA", 3000),
+	UPS_INFO_ENTRY(70, "LASER ONLINE 4000VA", 4000),
+	UPS_INFO_ENTRY(71, "LASER ONLINE 7500VA", 7500),
+	UPS_INFO_ENTRY(72, "LASER ONLINE BIFASICO 5000VA", 5000),
+	UPS_INFO_ENTRY(73, "LASER ONLINE BIFASICO 6000VA", 6000),
+	UPS_INFO_ENTRY(74, "LASER ONLINE BIFASICO 7500VA", 7500),
+	UPS_INFO_ENTRY(75, "NHS MINI ST", 500),
+	UPS_INFO_ENTRY(76, "NHS MINI 120", 120),
+	UPS_INFO_ENTRY(77, "NHS MINI BIVOLT", 500),
+	UPS_INFO_ENTRY(78, "PDV 600", 600),
+	UPS_INFO_ENTRY(79, "NHS MINI MAX", 500),
+	UPS_INFO_ENTRY(80, "NHS MINI EXT", 500),
+	UPS_INFO_ENTRY(81, "NHS AUTONOMY PDV 4T", 4000),
+	UPS_INFO_ENTRY(82, "NHS AUTONOMY PDV 8T", 8000),
+	UPS_INFO_ENTRY(83, "NHS COMPACT PLUS RACK 1200VA", 1200),
+	UPS_INFO_ENTRY(84, "PDV SENOIDAL ISOLADOR 1500VA", 1500),
+	UPS_INFO_ENTRY(85, "NHS PDV RACK 1500VA", 1500),
+	UPS_INFO_ENTRY(86, "NHS PDV 1400VA S GII", 1400),
+	UPS_INFO_ENTRY(87, "PDV SENOIDAL ISOLADOR 1500VA", 1500),
+	UPS_INFO_ENTRY(88, "LASER PRIME SENOIDAL ISOLADOR 2000VA", 2000),
+	UPS_INFO_ENTRY(89, "PREMIUM SENOIDAL 2400VA GII", 2400),
+	UPS_INFO_ENTRY(90, "NHS PDV 1400VA S 8T GII", 1400),
+	UPS_INFO_ENTRY(91, "PREMIUM ONLINE 2000VA", 2000),
+	UPS_INFO_ENTRY(92, "LASER PRIME ONLINE 2200VA", 2200),
+	UPS_INFO_ENTRY(93, "PREMIUM RACK ONLINE 2200VA", 2200),
+	UPS_INFO_ENTRY(94, "PREMIUM SENOIDAL 2400VA GII", 2400),
+	UPS_INFO_ENTRY(95, "LASER ONLINE 10000VA", 10000),
+	UPS_INFO_ENTRY(96, "LASER ONLINE BIFASICO 10000VA", 10000),
+	UPS_INFO_ENTRY(97, "LASER SENOIDAL 3300VA GII", 3300),
+	UPS_INFO_ENTRY(98, "LASER SENOIDAL 2600VA GII", 2600),
+	UPS_INFO_ENTRY(99, "PREMIUM SENOIDAL 3000VA GII", 3000),
+	UPS_INFO_ENTRY(100, "PREMIUM SENOIDAL 2200VA GII", 2200),
+	UPS_INFO_ENTRY(101, "LASER ONLINE BIFASICO 4000VA", 4000),
+	UPS_INFO_ENTRY(102, "LASER ONLINE 12000VA", 12000),
+	UPS_INFO_ENTRY(103, "LASER ONLINE 8000VA", 8000),
+	UPS_INFO_ENTRY(104, "PDV SENOIDAL ISOLADOR 1000VA", 1000),
+	UPS_INFO_ENTRY(105, "MINI SENOIDAL 500VA", 500),
+	UPS_INFO_ENTRY(106, "LASER SENOIDAL 5000VA GII", 5000),
+	UPS_INFO_ENTRY(107, "COMPACT PLUS SENOIDAL 1000VA", 1000),
+	UPS_INFO_ENTRY(108, "QUAD_COM 80A", 0),
+	UPS_INFO_ENTRY(109, "LASER ONLINE 5000VA", 5000),
+	UPS_INFO_ENTRY(113, "PDV SENOIDAL ISOLADOR 700VA", 700),
+};
 
-		case 106:
-			data.upscode = 106;
-			strncpy(data.upsdesc, "LASER SENOIDAL 5000VA GII", sizeof(data.upsdesc));
-			data.VA = 5000;
-			break;
+#undef UPS_INFO_ENTRY
 
-		case 107:
-			data.upscode = 107;
-			strncpy(data.upsdesc, "COMPACT PLUS SENOIDAL 1000VA", sizeof(data.upsdesc));
-			data.VA = 1000;
-			break;
+static upsinfo getupsinfo(unsigned int upscode) {
+	upsinfo	data = { (unsigned int)-1, "NHS UNKNOWN", 0, 3, 1 };
+	char	*overridemodel = getval("overridemodel");
+	char	*protocolversion = getval("protocolversion");
+	char	*bypassasalarm = getval("bypassasalarm");
 
-		case 108:
-			data.upscode = 108;
-			strncpy(data.upsdesc, "QUAD_COM 80A", sizeof(data.upsdesc));
-			data.VA = 0;
-			break;
+	if (upscode > 0 && upscode < sizeof(ups_info_table) / sizeof(ups_info_table[0]) && ups_info_table[upscode].upscode == upscode) {
+		data = ups_info_table[upscode];
+	} /* end if */
 
-		case 109:
-			data.upscode = 109;
-			strncpy(data.upsdesc, "LASER ONLINE 5000VA", sizeof(data.upsdesc));
-			data.VA = 5000;
-			break;
-
-		case 113:
-			data.upscode = 113;
-			strncpy(data.upsdesc, "PDV SENOIDAL ISOLADOR 700VA", sizeof(data.upsdesc));
-			data.VA = 700;
-			break;
+	/*
+	 * Protocol version 3 and bypass-as-alarm are initialized explicitly both in
+	 * the model table and in the synthetic unknown-model entry. Values supplied
+	 * in ups.conf customize only the returned copy, leaving the static table
+	 * unchanged. Protocol version is retained as model metadata for now and does
+	 * not select framing or initialization commands.
+	 */
+	if (overridemodel && overridemodel[0] != '\0') {
+		data.upscode = upscode;
+		snprintf(data.upsdesc, sizeof(data.upsdesc), "%s", overridemodel);
+	} /* end if */
+	if (protocolversion)
+		data.pversion = (unsigned int)atoi(protocolversion);
+	if (bypassasalarm)
+		data.bypassasalarm = (unsigned int)atoi(bypassasalarm);
 
-		default:
-			data.upscode = -1;
-			strncpy(data.upsdesc, "NHS UNKNOWN", sizeof(data.upsdesc));
-			data.VA = 0;
-			break;
-	}
 	return data;
 }
 
@@ -1857,7 +1314,7 @@ static unsigned int get_va(int equipment) {
 			return atoi(va);
 		else
 			fatalx(EXIT_FAILURE, "Please set VA (Volt Ampere) nominal capacity value to your equipment in ups.conf.");
-	}
+	}	/* end else */
 }
 
 static float get_pf(void) {
@@ -1884,6 +1341,46 @@ static float get_vin_perc(char * var) {
 		return DEFAULTPERC;
 }
 
+/*
+ * Send one hardware-discovery request only through a valid serial descriptor.
+ * If the descriptor is already invalid, try the driver's bounded reopen path.
+ * A failed or partial write closes and invalidates the descriptor so the next
+ * update cycle knows that it must reopen the port before communicating again.
+ */
+static bool send_initialization_packet(const unsigned int *data, size_t size, TYPE_FD_SER fd) {
+	int	written;
+
+	if (INVALID_FD_SER(fd)) {
+		upslogx(LOG_WARNING, "%s: serial port %s is not open before the initialization request; trying to reopen it", __func__, porta);
+		fd = reconnect_ups_if_needed();
+		if (INVALID_FD_SER(fd)) {
+			upslogx(LOG_WARNING, "%s: unable to send the initialization request because serial port %s could not be reopened", __func__, porta);
+			dstate_datastale();
+			return false;
+		}	/* end if */
+	}	/* end if */
+
+	upsdebugx(3, "%s: sending initialization request (%" PRIuSIZE " bytes) on %s", __func__, size, porta);
+	errno = 0;
+	written = write_serial_int(fd, data, size);
+	if (written < 0 || (size_t)written != size) {
+		if (errno != 0)
+			upslog_with_errno(LOG_WARNING, "%s: failed to send the initialization request on %s", __func__, porta);
+		else
+			upslogx(LOG_WARNING, "%s: failed to send the complete initialization request on %s; wrote %d of %" PRIuSIZE " bytes", __func__, porta, written, size);
+
+		/* Mark the connection unusable. upsdrv_updateinfo() will invoke the
+		 * normal reopen procedure before its next read or retry.
+		 */
+		close_serial_port();
+		dstate_datastale();
+		return false;
+	}	/* end if */
+
+	upsdebugx(3, "%s: initialization request sent successfully on %s", __func__, porta);
+	return true;
+}
+
 void upsdrv_initinfo(void) {
 	/* From docs/new-drivers.txt:
 	 * Try to detect what kind of UPS is out there,
@@ -1900,6 +1397,16 @@ void upsdrv_initinfo(void) {
 	upsdebugx(3, "%s: starting...", __func__);
 
 	/* TODO: Any instant commands? */
+	if (!send_initialization_packet(string_initialization_long, 9, serial_fd))
+		return;
+	usleep(250000);
+	if (!send_initialization_packet(string_initialization_short, 9, serial_fd))
+		return;
+	usleep(250000);
+	if (!send_initialization_packet(string_initialization_comptmode, 5, serial_fd))
+		return;
+
+	upsdebugx(3, "%s: initialization commands sent", __func__);
 
 	upsdebugx(3, "%s: finished", __func__);
 }
@@ -1925,11 +1432,11 @@ static unsigned int get_numbat(void) {
 static TYPE_FD_SER reconnect_ups_if_needed(void) {
 	/* retries to open port until we declare "data stale" loudly */
 	static unsigned int	retries = 0;
+	bool	retry_limit_reached = false;
 
 	/* If comms failed earlier, try to resuscitate */
 	if (INVALID_FD_SER(serial_fd)) {
-		upsdebugx(1, "%s: Serial port '%s' communications problem",
-			__func__, porta);
+		upsdebugx(1, "%s: Serial port '%s' communications problem", __func__, porta);
 
 		/* Uh oh, got to reconnect! */
 		reconnect_trying(RECONNECT_TRYING);
@@ -1937,31 +1444,38 @@ static TYPE_FD_SER reconnect_ups_if_needed(void) {
 		/* Close any surviving handle and mark it invalid before reopening. */
 		close_serial_port();
 
-		while (INVALID_FD_SER(serial_fd)) {
+		while (INVALID_FD_SER(serial_fd) && !retry_limit_reached) {
 			upsdebugx(1, "%s: Trying to reopen serial...", __func__);
 			serial_fd = openfd(porta, baudrate);
 			retries++;
-			/* Try above at least once per main cycle */
 			if (retries >= MAXTRIES) {
 				upsdebugx(1, "%s: serial port reopen failed", __func__);
-				break;
-			}
-			usleep(checktime);
-		}
+				retry_limit_reached = true;
+			}	/* end if */
+			else
+				usleep(checktime);
+		}	/* end while */
 
 		if (VALID_FD_SER(serial_fd)) {
-			if (retries > MAXTRIES && may_log_reconnect_trying(1)) {
+			if (retries > MAXTRIES && may_log_reconnect_trying(1))
 				upslogx(LOG_NOTICE, "Communications with UPS re-established");
-			}
+
+			/* A reopened serial port may now be connected to a different UPS.
+			 * Invalidate the cached discovery result and restart the initialization
+			 * sequence so model-specific data is obtained without restarting NUT.
+			 */
+			lastpkthwinfo.checksum_ok = false;
+			send_extended = 0;
+			checktime = 2000000;
 			retries = 0;
 			reconnect_trying(RECONNECT_SUCCESS);
-		} else {
-			if (retries == MAXTRIES && may_log_reconnect_trying(1)) {
+		}	/* end if */
+		else {
+			if (retries == MAXTRIES && may_log_reconnect_trying(1))
 				upslogx(LOG_WARNING, "Communications with UPS lost: port reopen failed!");
-			}
 			dstate_datastale();
-		}
-	}
+		}	/* end else */
+	}	/* end if */
 
 	return serial_fd;
 }
@@ -1970,33 +1484,31 @@ static void interpret_pkt_hwinfo(void) {
 	/* TOTHINK: Consider passing in the packet struct as parameter? */
 	upsinfo	ups;
 	char	hw_scratch_buf[1024];	/* General-purpose string buffer */
+	unsigned int	i = 0;
 
-	if (!lastpktdata.checksum_ok) {
-		upslogx(LOG_WARNING, "%s: bad lastpkthwinfo.checksum",
-			__func__);
+	/* @freechurros identified in issue #3592 that this function used to
+	 * inspect lastpktdata here. Validate the HWINFO packet being interpreted,
+	 * otherwise a valid HWINFO received before the first DATA packet is lost.
+	 */
+	if (!lastpkthwinfo.checksum_ok) {
+		upslogx(LOG_WARNING, "%s: bad lastpkthwinfo.checksum", __func__);
 		return;
-	}
+	}	/* end if */
 
 	if (lastpkthwinfo.size < 1) {
-		upslogx(LOG_WARNING, "%s: Pkt HWINFO is not OK. "
-			"See if will be requested next time!",
-			__func__);
+		upslogx(LOG_WARNING, "%s: Pkt HWINFO is not OK. See if will be requested next time!", __func__);
 		return;
-	}
+	}	/* end if */
 
 	/* checksum is OK, then use it to set values */
-	upsdebugx(4, "Pkt HWINFO is OK. Model code is %u, hwversion is %u "
-		"and swversion is %u",
-		lastpkthwinfo.model,
-		lastpkthwinfo.hardwareversion,
-		lastpkthwinfo.softwareversion);
+	upsdebugx(4, "Pkt HWINFO is OK. Model code is %u, hwversion is %u and swversion is %u", lastpkthwinfo.model, lastpkthwinfo.hardwareversion, lastpkthwinfo.softwareversion);
 
 	/* We need to set data on NUT with data
 	 * that I believe that I can calculate.
 	 * Now setting data on NUT
 	 */
 	ups = getupsinfo(lastpkthwinfo.model);
-	upsdebugx(4, "UPS Struct data: Code %u Model %s VA %u", ups.upscode, ups.upsdesc, ups.VA);
+	upsdebugx(4, "UPS Struct data: Code %u Model %s VA %u Protocol version %u Bypass as alarm %u", ups.upscode, ups.upsdesc, ups.VA, ups.pversion, ups.bypassasalarm);
 	dstate_setinfo("device.model", "%s", ups.upsdesc);
 	dstate_setinfo("device.mfr", "%s", MANUFACTURER);
 	dstate_setinfo("device.serial", "%s", lastpkthwinfo.serial);
@@ -2015,8 +1527,6 @@ static void interpret_pkt_hwinfo(void) {
 	dstate_setinfo("ups.firmware.aux", "%u", lastpkthwinfo.hardwareversion);
 
 	if (debug_pkt_hwinfo) {
-		unsigned int	i = 0;
-
 		/* Now, creating a structure called NHS.HW, for latest HW
 		 * info packet contents and raw data points, including those
 		 * that were sorted above into NUT standard variables -
@@ -2033,7 +1543,7 @@ static void interpret_pkt_hwinfo(void) {
 			/* Reusing variable */
 			snprintf(hw_scratch_buf, sizeof(hw_scratch_buf), "experimental.nhs.hw.configuration_array_p%u", i);
 			dstate_setinfo(hw_scratch_buf, "%u", lastpkthwinfo.configuration_array[i]);
-		}
+		}	/* end for */
 		dstate_setinfo("experimental.nhs.hw.c_oem_mode", "%s", lastpkthwinfo.c_oem_mode ? "true" : "false");
 		dstate_setinfo("experimental.nhs.hw.c_buzzer_disable", "%s", lastpkthwinfo.c_buzzer_disable ? "true" : "false");
 		dstate_setinfo("experimental.nhs.hw.c_potmin_disable", "%s", lastpkthwinfo.c_potmin_disable ? "true" : "false");
@@ -2051,7 +1561,7 @@ static void interpret_pkt_hwinfo(void) {
 			/* Reusing variable */
 			snprintf(hw_scratch_buf, sizeof(hw_scratch_buf), "experimental.nhs.hw.status_p%u", i);
 			dstate_setinfo(hw_scratch_buf, "%u", lastpkthwinfo.status[i]);
-		}
+		}	/* end for */
 		dstate_setinfo("experimental.nhs.hw.s_220V_in", "%s", lastpkthwinfo.s_220V_in ? "true" : "false");
 		dstate_setinfo("experimental.nhs.hw.s_220V_out", "%s", lastpkthwinfo.s_220V_out ? "true" : "false");
 		dstate_setinfo("experimental.nhs.hw.s_sealed_battery", "%s", lastpkthwinfo.s_sealed_battery ? "true" : "false");
@@ -2077,7 +1587,7 @@ static void interpret_pkt_hwinfo(void) {
 		dstate_setinfo("experimental.nhs.hw.alarmminute", "%u", lastpkthwinfo.alarmminute);
 		dstate_setinfo("experimental.nhs.hw.alarmsecond", "%u", lastpkthwinfo.alarmsecond);
 		dstate_setinfo("experimental.nhs.hw.end_marker", "%u", lastpkthwinfo.end_marker);
-	}
+	}	/* end if */
 }
 
 static void interpret_pkt_data(void) {
@@ -2108,22 +1618,20 @@ static void interpret_pkt_data(void) {
 	long	bcharge = 0;
 	float	abat = 0;
 	float	actual_current = 0;
+	unsigned int	i = 0;
+	upsinfo	ups;
 
 	if (!lastpktdata.checksum_ok) {
 		upslogx(LOG_WARNING, "%s: bad lastpktdata.checksum", __func__);
 		return;
-	}
+	}	/* end if */
 
 	/* checksum is OK, then use it to set values */
 	upsdebugx(4, "%s: Data Packet seems be OK", __func__);
 
-	if (!got_hwinfo) {
-		upsdebugx(2, "%s: Pkt HWINFO is not OK. "
-			"See if will be requested next time. "
-			"Some data points will not be set on this pass!",
-			__func__);
-		/* Not return, but we would miss some data points */
-	}
+	/* Not return, but we would miss some data points */
+	if (!got_hwinfo)
+		upsdebugx(2, "%s: Pkt HWINFO is not OK. See if will be requested next time. Some data points will not be set on this pass!", __func__);
 
 	/* Setting UPS Status:
 	 * OL	  -- On line (mains is present): Code below
@@ -2145,24 +1653,24 @@ static void interpret_pkt_data(void) {
 	/* Decision Chain commented below */
 
 	/* First we check if system is on battery or not */
-	upsdebugx(4, "Set UPS status as OFF and start checking. s_battery_mode is %d",
-		lastpktdata.s_battery_mode);
+	upsdebugx(4, "Set UPS status as OFF and start checking. s_battery_mode is %d", lastpktdata.s_battery_mode);
 
 	if (got_hwinfo) {
 		if (lastpkthwinfo.s_220V_in) {
 			upsdebugx(4, "I'm on 220v IN!. My undervoltage is %u", lastpkthwinfo.undervoltagein220V);
 			min_input_power = lastpkthwinfo.undervoltagein220V;
-		}
+		}	/* end if */
 		else {
 			upsdebugx(4, "I'm on 120v IN!. My undervoltage is %u", lastpkthwinfo.undervoltagein120V);
 			min_input_power = lastpkthwinfo.undervoltagein120V;
-		}
-	} else {
+		}	/* end else */
+	}	/* end if */
+	else {
 		if (!min_input_power) {
 			min_input_power = 96;
 			upsdebugx(4, "I'm on unknown input!. My undervoltage is default %d", min_input_power);
-		}
-	}
+		}	/* end if */
+	}	/* end else */
 
 	/* No ups.status changes above this line */
 	status_init();
@@ -2181,12 +1689,7 @@ static void interpret_pkt_data(void) {
 		/* Check if MAINS (power) is not preset.
 		 * Well, we can check pkt_data.s_network_failure too... */
 		if ((lastpktdata.vacinrms <= min_input_power) || (lastpktdata.s_network_failure)) {
-			upsdebugx(4, "UPS has power-in value %0.2f "
-				"and min_input_power is %d, "
-				"or network is in failure. Network failure is %d",
-				lastpktdata.vacinrms,
-				min_input_power,
-				lastpktdata.s_network_failure);
+			upsdebugx(4, "UPS has power-in value %0.2f and min_input_power is %d, or network is in failure. Network failure is %d", lastpktdata.vacinrms, min_input_power, lastpktdata.s_network_failure);
 			status_set("DISCHRG");
 		}	/* end if */
 		else {
@@ -2200,7 +1703,7 @@ static void interpret_pkt_data(void) {
 				if (lastpktdata.s_charger_on) {
 					upsdebugx(4, "UPS Charging...");
 					status_set("CHRG");
-				}
+				}	/* end if */
 				else {
 					if ((lastpktdata.s_network_failure) || (lastpktdata.s_fast_network_failure)) {
 						upsdebugx(4, "UPS is on battery mode because network failure or fast network failure");
@@ -2217,10 +1720,9 @@ static void interpret_pkt_data(void) {
 				* Nobreak is probably in battery mode... */
 				if (lastpktdata.s_battery_low)
 					status_set("LB");
-				else {
+				else
 					/* ...or network failure */
 					status_set("OB");
-				}	/* end else */
 			}	/* end else */
 		}	/* end else */
 	}	/* end else */
@@ -2245,14 +1747,20 @@ static void interpret_pkt_data(void) {
 			numbat = lastpkthwinfo.numbatteries;
 		else
 			upsdebugx(4, "Number of batteries is set to %u", numbat);
-	}
+	}	/* end if */
 
 	/* No ups.alarm changes above this line */
 	alarm_init();
+	ups = getupsinfo(lastpkthwinfo.model);
 
 	if (lastpktdata.s_battery_low)
 		alarm_set("[LOW BATTERY]");
-	if (lastpktdata.s_bypass_on)
+	/*
+	 * Some line-interactive models keep the decoded bypass bit set during normal
+	 * on-line operation. A zero bypassasalarm setting preserves the decoded bit
+	 * for diagnostics without publishing a permanent [ON BYPASS] alarm.
+	 */
+	if (lastpktdata.s_bypass_on && ups.bypassasalarm == 1)
 		alarm_set("[ON BYPASS]");
 
 	if (lastpktdata.s_network_failure)
@@ -2303,12 +1811,13 @@ static void interpret_pkt_data(void) {
 			minpowerperc = lastpktdata.potrms;
 		dstate_setinfo("output.power.maximum.percent", "%u", maxpowerperc);
 		dstate_setinfo("output.power.minimum.percent", "%u", minpowerperc);
-	}
+	}	/* end if */
 
 	dstate_setinfo("output.voltage", "%0.2f", lastpktdata.vacoutrms);
 	dstate_setinfo("input.voltage", "%0.2f", lastpktdata.vacinrms);
-	dstate_setinfo("input.voltage.maximum", "%0.2f", lastpktdata.vacinrmsmin);
-	dstate_setinfo("input.voltage.minimum", "%0.2f", lastpktdata.vacinrmsmax);
+	/* Map the packet's observed minimum and maximum to their matching NUT names. */
+	dstate_setinfo("input.voltage.maximum", "%0.2f", lastpktdata.vacinrmsmax);
+	dstate_setinfo("input.voltage.minimum", "%0.2f", lastpktdata.vacinrmsmin);
 
 	if (got_hwinfo) {
 		dstate_setinfo("ups.beeper.status", "%d", !lastpkthwinfo.c_buzzer_disable);
@@ -2334,7 +1843,7 @@ static void interpret_pkt_data(void) {
 		dstate_setinfo("input.voltage.nominal", "%u", vin);
 		vout = lastpkthwinfo.s_220V_out ? lastpkthwinfo.tensionout220V : lastpkthwinfo.tensionout120V;
 		dstate_setinfo("output.voltage.nominal", "%u", vout);
-	}
+	}	/* end if */
 
 	/* Battery electric info */
 	bcharge = lrint(round((lastpktdata.vdcmed_real * 100) / vbat));
@@ -2370,21 +1879,23 @@ static void interpret_pkt_data(void) {
 		autonomy_secs = (ah / actual_current) * 3600;
 
 		dstate_setinfo("battery.runtime", "%u", autonomy_secs);
-	}
+	}	/* end if */
 
-	/* Battery charger status */
-	if (lastpktdata.s_charger_on) {
-		dstate_setinfo("battery.charger.status", "%s", "CHARGING");
-	} else {
+	/* Battery charger status
+	 * @freechurros reported in issue #3592 that Home Assistant rejects the
+	 * former upper-case strings. Use the lower-case vocabulary documented in
+	 * docs/nut-names.txt for interoperability with NUT clients.
+	 */
+	if (lastpktdata.s_charger_on)
+		dstate_setinfo("battery.charger.status", "%s", "charging");
+	else {
 		if (lastpktdata.s_battery_mode)
-			dstate_setinfo("battery.charger.status", "%s", "DISCHARGING");
+			dstate_setinfo("battery.charger.status", "%s", "discharging");
 		else
-			dstate_setinfo("battery.charger.status", "%s", "RESTING");
-	}
+			dstate_setinfo("battery.charger.status", "%s", "resting");
+	}	/* end else */
 
 	if (debug_pkt_data) {
-		unsigned int	i = 0;
-
 		/* Now, creating a structure called NHS.DATA, for latest
 		 * data packet contents and raw data points, including those
 		 * that were sorted above into NUT standard variables -
@@ -2423,7 +1934,7 @@ static void interpret_pkt_data(void) {
 			/* Reusing variable */
 			snprintf(data_scratch_buf, sizeof(data_scratch_buf), "experimental.nhs.data.status_p%u", i);
 			dstate_setinfo(data_scratch_buf, "%u", lastpktdata.status[i]);
-		}
+		}	/* end for */
 		dstate_setinfo("experimental.nhs.data.nominaltension", "%u", lastpktdata.nominaltension);
 		dstate_setinfo("experimental.nhs.data.timeremain", "%0.2f", lastpktdata.timeremain);
 		dstate_setinfo("experimental.nhs.data.s_battery_mode", "%s", lastpktdata.s_battery_mode ? "true" : "false");
@@ -2445,12 +1956,16 @@ static void interpret_pkt_data(void) {
 		dstate_setinfo("experimental.nhs.param.vin_low_crit_perc", "%0.2f", get_vin_perc("vin_low_crit_perc"));
 		dstate_setinfo("experimental.nhs.param.vin_high_warn_perc", "%0.2f", get_vin_perc("vin_high_warn_perc"));
 		dstate_setinfo("experimental.nhs.param.vin_high_crit_perc", "%0.2f", get_vin_perc("vin_high_crit_perc"));
-	}
+	}	/* end if */
 }
 
 void upsdrv_updateinfo(void) {
 	double	tempodecorrido = 0.0;
-	time_t	now;
+	time_t	now, timeout_sec;
+	useconds_t	timeout_usec;
+	ssize_t	read_result;
+	int	randval = 0;
+	pkt_hwinfo	received_hwinfo;
 
 	upsdebugx(3, "%s: starting...", __func__);
 
@@ -2459,96 +1974,115 @@ void upsdrv_updateinfo(void) {
 		return;
 
 	chr = '\0';
-	{
-		ssize_t	read_result;
 
-		/* ser_get_char accepts separate seconds and microseconds components. */
-		time_t		timeout_sec = (time_t)(serial_read_timeout_ms / 1000);
-		useconds_t	timeout_usec =
-			(useconds_t)((serial_read_timeout_ms % 1000) * 1000);
+	/* ser_get_char accepts separate seconds and microseconds components. */
+	timeout_sec = (time_t)(serial_read_timeout_ms / 1000);
+	timeout_usec = (useconds_t)((serial_read_timeout_ms % 1000) * 1000);
 
-		/*
-		 * A positive result supplies one byte, zero is the configured normal
-		 * timeout, and a negative result is handled as a communication error.
+	/*
+	 * A positive result supplies one byte, zero is the configured normal
+	 * timeout, and a negative result is handled as a communication error.
+	 */
+	read_result = ser_get_char(serial_fd, &chr, timeout_sec, timeout_usec);
+	while (read_result > 0) {
+		/* The length-aware framing and the need to preserve marker values inside
+		 * packet payloads were demonstrated by raw captures contributed by
+		 * @freechurros in issue #3592.
+		 *
+		 * A 0xFF byte starts a packet only while the reader is idle. After
+		 * the packet starts, byte [1] declares its total size, including the
+		 * initial 0xFF, checksum and final 0xFE. Any 0xFF or 0xFE received
+		 * before the declared final position belongs to the packet contents.
+		 * The packet is interpreted only when byte [size - 1] is 0xFE.
 		 */
-		while ((read_result = ser_get_char(
-			serial_fd,
-			&chr,
-			timeout_sec,
-			timeout_usec
-		)) > 0) {
-			if (chr == 0xFF) {	/* DataPacket start */
-				datapacketstart = true;
-				memset(datapacket, 0, sizeof(datapacket));
-				datapacket_index = 0;
-			}
-			if (datapacketstart) {
-				datapacket[datapacket_index] = chr;
-				datapacket_index++;
-				if (chr == 0xFE) {	/* DataPacket */
-					break;
-				}
-				if (datapacket_index >= sizeof(datapacket)) {
-					upslogx(LOG_WARNING, "Incoming packet does not seem to end, discarding!");
-					datapacketstart = false;
-					break;
-				}
-			}
-		}
+		if ((chr == 0xFF) && (!datapacketstart)) {
+			datapacketstart = true;
+			memset(datapacket, 0, sizeof(datapacket));
+			datapacket_index = 0;
+			datapacketsize = 0;
+		}	/* end if */
+		if (datapacketstart) {
+			/* Assume that second position is PACKET SIZE. */
+			if (datapacket_index == 1)
+				datapacketsize = chr;
+			datapacket[datapacket_index] = chr;
+			if ((datapacket_index == 1) && ((datapacketsize < 18) || (datapacketsize > sizeof(datapacket)))) {
+				upslogx(LOG_WARNING, "Incoming packet declares an invalid size, discarding!");
+				datapacketstart = false;
+			}	/* end if */
+			else {
+				if ((datapacketsize > 0) && (datapacket_index == (datapacketsize - 1))) {
+					if (datapacket[datapacket_index] != 0xFE)
+						upslogx(LOG_WARNING, "Incoming packet does not end with 0xFE, discarding!");
+					else {
+						now = time(NULL);
+						upsdebugx(4, "DATAPACKET SIZE IS %u", datapacketsize);
+
+						if (lastdp != 0)
+							tempodecorrido = difftime(now, lastdp);
+
+						lastdp = now;
+
+						switch (datapacketsize) {
+							case 18:
+							case 50:
+								received_hwinfo = mount_hwinfo(datapacket, datapacketsize);
+
+								/* Always accept a new valid HWINFO packet. The UPS may be
+								 * replaced while the driver remains active, so retaining only
+								 * the first packet would leave model-specific data stale until
+								 * NUT is restarted. Preserve the last valid data if the newly
+								 * received packet has a bad checksum.
+								 */
+								if (received_hwinfo.checksum_ok) {
+									lastpkthwinfo = received_hwinfo;
+									interpret_pkt_hwinfo();
+									dstate_dataok();
+								}	/* end if */
+								break;
+
+							case 21:
+								lastpktdata = mount_datapacket(datapacket, datapacketsize, tempodecorrido, lastpkthwinfo);
+
+								if (lastpktdata.checksum_ok) {
+									interpret_pkt_data();
+									dstate_dataok();
+								}	/* end if */
+								break;
+
+							default:
+								upslogx(LOG_WARNING, "Incoming packet size not recognized, discarding!");
+								/* Suggested by @freechurros in issue #3592: expose the
+								 * rejected bytes when raw packet debugging is enabled so
+								 * future framing variants can be diagnosed from the log.
+								 */
+								pdatapacket(datapacket, datapacketsize);
+								break;
+						}	/* end switch */
+					}	/* end else */
 
-		if (read_result < 0) {
-			upsdebug_with_errno(1, "%s: Serial read failed on %s",
-				__func__, porta);
-			close_serial_port();
-			dstate_datastale();
-			return;
-		}
-	}
+					datapacketstart = false;
+				}	/* end if */
+			}	/* end else */
+		}	/* end if */
+		/* Advance only after consuming the current byte. Keeping both the
+		 * index and declared size outside this function lets a packet resume
+		 * at the correct position after a normal serial-read timeout.
+		 */
+		datapacket_index++;
+		read_result = ser_get_char(serial_fd, &chr, timeout_sec, timeout_usec);
+	}	/* end while */
 
-	if (chr != 0xFE || !datapacketstart) {
+	if (read_result < 0) {
+		upsdebug_with_errno(1, "%s: Serial read failed on %s", __func__, porta);
+		close_serial_port();
+		dstate_datastale();
+		return;
+	}	/* end if */
+	if (datapacketstart) {
 		upsdebugx(2, "%s: packet reading did not finish, not interpreting yet", __func__);
 		return;
-	}
-
-	/* Interpret the just-finished packet buffer */
-	now = time(NULL);
-	upsdebugx(4, "DATAPACKET INDEX IS %" PRIuSIZE, datapacket_index);
-	if (lastdp != 0) {
-		tempodecorrido = difftime(now, lastdp);
-	}
-	lastdp = now;
-
-	/* Parse the bytes into a structure to handle below:
-	 * If size is 18 or 50, may be an answer packet.
-	 * Then check if doesn't have already a packet processed.
-	 * We don't need to read all times these information.
-	 * Can be a corrupted packet too.
-	 */
-	if (((datapacket_index == 18) || (datapacket_index == 50)) && (!lastpkthwinfo.checksum_ok)) {
-		/* Re-read HW info only if the old one is broken */
-		lastpkthwinfo = mount_hwinfo(datapacket, datapacket_index);
-		if (lastpkthwinfo.checksum_ok) {
-			interpret_pkt_hwinfo();
-			/* Refresh the healthy timer */
-			dstate_dataok();
-		}
 	}	/* end if */
-	else if (datapacket_index == 21) {
-		lastpktdata = mount_datapacket(datapacket, datapacket_index, tempodecorrido, lastpkthwinfo);
-		if (lastpktdata.checksum_ok) {
-			interpret_pkt_data();
-			/* Refresh the healthy timer */
-			dstate_dataok();
-		}
-	}	/* end else-if */
-	else {
-		upslogx(LOG_WARNING, "Incoming packet size not recognized, discarding!");
-	}	/* end else */
-
-	/* Clean datapacket structure to avoid problems for next parse */
-	datapacket_index = 0;
-	memset(datapacket, 0, sizeof(datapacket));
-	datapacketstart = false;
 
 	/* Now the nobreak read buffer is empty.
 	 * We need a hw info packet to discover several variables,
@@ -2559,8 +2093,8 @@ void upsdrv_updateinfo(void) {
 		upsdebugx(4, "pkt_hwinfo loss -- Requesting");
 		/* If size == 0, packet maybe not initizated,
 		 * then send an initialization packet to obtain data.
-		 * Send two times the extended initialization string,
-		 * but, on fail, try randomly send extended or normal.
+		 * Send six times the extended initialization string,
+		 * but, on fail, try randomly send extended, normal or compatibility.
 		 */
 		if (send_extended < 6) {
 			upsdebugx(4, "Sending extended initialization packet. Try %u", send_extended+1);
@@ -2569,20 +2103,34 @@ void upsdrv_updateinfo(void) {
 		}	/* end if */
 		else {
 			/* randomly send */
-			if (rand() % 2 == 0) {
-				upsdebugx(4, "Sending long initialization packet");
-				bwritten = write_serial_int(serial_fd, string_initialization_long, 9);
-			}	/* end if */
-			else {
-				upsdebugx(4, "Sending short initialization packet");
-				bwritten = write_serial_int(serial_fd, string_initialization_short, 9);
-			}	/* end else */
+			randval = rand() % 3;
+			switch (randval) {
+				case 0:
+					upsdebugx(4, "Sending long initialization packet (random)");
+					bwritten = write_serial_int(serial_fd, string_initialization_long, 9);
+					break;
+				case 1:
+					upsdebugx(4, "Sending short initialization packet (random)");
+					bwritten = write_serial_int(serial_fd, string_initialization_short, 9);
+					break;
+				case 2:
+					upsdebugx(4, "Sending compatibility initialization packet (random)");
+					bwritten = write_serial_int(serial_fd, string_initialization_comptmode, 5);
+					break;
+				default:
+					/* rand() % 3 currently limits this switch to cases 0..2.
+					 * Keep a deterministic fallback so future changes to the
+					 * selection range cannot leave bwritten with stale data.
+					 */
+					upsdebugx(4, "Initialization selection out of range; sending long packet");
+					bwritten = write_serial_int(serial_fd, string_initialization_long, 9);
+					break;
+			}	/* end switch */
 		}	/* end else */
 		if (bwritten < 0) {
 			upsdebugx(1, "%s: Problem to write data to %s", __func__, porta);
-			if (bwritten == -1) {
+			if (bwritten == -1)
 				upsdebugx(1, "%s: Data problem", __func__);
-			}
 			close_serial_port();
 		}	/* end if */
 		else {
@@ -2591,10 +2139,10 @@ void upsdrv_updateinfo(void) {
 			else {
 				upsdebugx(3, "Increase checktime to %u", checktime + 100000);
 				checktime = checktime + 100000;
-			}
+			}	/* end else */
 			usleep(checktime);
 		}	/* end else */
-	}	/* end if lastpkthwinfo good/bad checksum */
+	}	/* end if lastpkthwinfo good/bad checksum */	/* end if */
 
 	upsdebugx(3, "%s: finished", __func__);
 }
@@ -2642,8 +2190,7 @@ void upsdrv_initups(void) {
 	/* Validate the complete serial configuration before accessing the device. */
 	parse_serial_options();
 
-	upsdebugx(1, "%s: Port is %s and baud_rate is %d",
-		__func__, device_path, baudrate);
+	upsdebugx(1, "%s: Port is %s and baud_rate is %d", __func__, device_path, baudrate);
 
 	if (device_path) {
 		if (strcasecmp(device_path, "auto") == 0)
@@ -2652,13 +2199,10 @@ void upsdrv_initups(void) {
 			strncpy(porta, device_path, sizeof(porta) - 1);
 		serial_fd = openfd(porta, baudrate);
 		if (INVALID_FD_SER(serial_fd))
-			fatalx(EXIT_FAILURE, "Unable to open port %s with baud %d",
-				porta, baudrate);
-		else {
-			upsdebugx(1, "%s: Communication started on port %s, baud rate %d",
-				__func__, porta, baudrate);
-		}
-	}
+			fatalx(EXIT_FAILURE, "Unable to open port %s with baud %d", porta, baudrate);
+		else
+			upsdebugx(1, "%s: Communication started on port %s, baud rate %d", __func__, porta, baudrate);
+	}	/* end if */
 	else
 		fatalx(EXIT_FAILURE, "Unable to define port and baud");
 
@@ -2720,6 +2264,12 @@ void upsdrv_makevartable(void) {
 	addvar(VAR_FLAG, "debug_pkt_data", "Enable debug logging of data packet decoding");
 
 	addvar(VAR_FLAG, "debug_pkt_hwinfo", "Enable debug logging of hwinfo packet decoding");
+
+	addvar(VAR_VALUE, "overridemodel", "Override the UPS model name reported by the driver");
+
+	addvar(VAR_VALUE, "protocolversion", "Override the NHS protocol version stored for the model (default: 3)");
+
+	addvar(VAR_VALUE, "bypassasalarm", "Report the UPS bypass bit as an alarm: 0 or 1 (default: 1)");
 }
 
 void upsdrv_help(void) {