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www.unavlab.com support@unavlab.com	RedGTR - code communication underwater acoustic modem Communication protocol specification

RedGTR
communication protocol specification

Contents

• 1. Introduction
  • 1.1. Physical layer
  • 1.2. NMEA0183 Protocol standard
• 2. TNT Command System for RedGTR modems
  • 2.1. IC_D2H_ACK
  • 2.2. IC_H2D_LOC_DATA_GET
  • 2.3. IC_H2D_LOC_DATA_SET
  • 2.4. IC_D2H_LOC_DATA_VAL
  • 2.5. IC_D2H_DEV_INFO
  • 2.6. IC_H2D_ACT_INVOKE
  • 2.7. IC_H2D_REM_SEND
  • 2.8. IC_H2D_REM_PING
  • 2.9. IC_H2D_REM_PINGEX
  • 2.10. IC_D2H_REM_RECEIVED
  • 2.11. IC_D2H_REM_TOUT
  • 2.12. IC_D2H_REM_PONG
  • 2.13. IC_D2H_REM_PONGEX
• 3. Identifiers
  • 3.1. Device type identifiers
  • 3.2. Error messages
  • 3.3. Local data identifier
  • 3.4. Service actions identifiers
  • 3.5. Remote requests identifiers

1. Introduction

1.1. Physical layer

RedGTR underwater acoustic modems support data pairing using the RS-232 physical layer standard for asynchronous interface (UART) with a 3.3V data line voltage. The connection is made using a four-wire cable with Tx (transmitter), Rx (receiver), Vcc (power) and GND (ground) wires. Without the use of additional repeaters and interface converters, the maximum cable length, for which the correct operation of the interface is guaranteed, is no more than 2 meters.

Default port settings¹:

Baudrate: 9600 bit/s
Data bits: 8
Stop bits: 1
Parity: No
Hardware flow control: No

WARNING! The modems are powered by 12 Volt DC source, while the data line voltage is 3.3 V.

1.2. NMEA0183 Protocol standard

The NMEA0183 standard describes the format of text (ASCII) messages at the interactive level.

Sentence example: $PTNT0,1*hh<СR><LF>

Parts of a message (sentence) NMEА0183:

• ’$’ - sentence start,
• ‘P’ - Proprietary
• ‘TNT’ - Manufacturer/protocol identifier
• ‘0’ - sentence identifier
• ’,’ - parameters separator
• ‘*’ - checksum separator
• ‘hh’ - checksum in hexadecimal format (for example FF, 01). Byte-by-byte XOR for all characters between ‘$’ and ‘*’.
• <CR><LF> - end of sentence ____ ¹ Specified parameters can be changed by a request

2. TNT Command System for RedGTR modems

The D2H prefix in the message name means that it is transmitted from the device (Device) to the host system (Host). The H2D prefix in the message name means that it is transmitted from the host system to the device.

2.1. IC_D2H_ACK

Device acknowledgement.

Format: $PTNT0,x*hh<CR><LF>

№	Field/Parameter	Description
	$	Sentence start ‘$’
	P	Proprietary sentence
	TNT	Proprietery code ID
	0	Sentence ID
1	errCode	Error code (see 3.2.)
	*	NMEA checksum separator
	hh	NMEA checksum
	<CR><LF>	end of sentence

2.2. IC_H2D_LOC_DATA_GET

Query for a local parameter value.

Format: $PTNT4,xx,00*hh<CR><LF>

№	Field/Parameter	Description
	$	Sentence start ‘$’
	P	Proprietary sentence
	TNT	Proprietery code ID
	4	Sentence ID
1	dataID	Parameter ID (see 3.3.)
2	reserved	should be ‘00’
	*	NMEA checksum separator
	hh	NMEA checksum
	<CR><LF>	end of sentence

2.3. IC_H2D_LOC_DATA_SET

Setting a value of a local parameter (see 3.3.).

Format: $PTNT7,xx,00*hh<CR><LF>

№	Field/Parameter	Description
	$	Sentence start ‘$’
	P	Proprietary sentence
	TNT	Proprietery code ID
	7	Sentence ID
1	Requested data ID	Local parameter identifier (see 3.3.)
2	Reserved	Reserved, should always be ‘00’
	*	NMEA checksum separator
	hh	NMEA checksum
	<CR><LF>	end of sentence

2.4. IC_D2H_LOC_DATA_VAL

Device’s response to IC_H2D_LOC_DATA_GET sentence.

Format: $PTNT5,x,x<CR><LF>

№	Field/Parameter	Description
	$	Sentence start ‘$’
	P	Proprietary sentence
	TNT	Proprietery code ID
	5	Sentence ID
1	Requested data ID	Parameter ID (see 3.3.)
2	Value	Queried value
	*	NMEA checksum separator
	hh	NMEA checksum
	<CR><LF>	end of sentence

2.5. IC_D2H_DEV_INFO

Device’s responce to IC_D2H_LOC_DATA_GET, if the queried parameter ID = LOC_DATA_DEV_INFO.

Format: $PTNT!,c--c,x,x,c--c,x,c--c<CR><LF>

№	Field/Parameter	Description
	$	Sentence start ‘$’
	P	Proprietary sentence
	TNT	Proprietery code ID
	!	Sentence ID
1	System moniker	System name
2	System version	System version (BCD)
3	Communication subsystem moniker	Communication subsystem name
4	Communication subsystem version	Communication subsystem version (BCD)
5	Device type	Device type (see 3.1.)
6	Serial number	Serial number
	*	NMEA checksum separator
	hh	NMEA checksum
	<CR><LF>	end of sentence

2.6. IC_H2D_ACT_INVOKE

Service action request.

Format: $PTNT6,xx,00*hh<CR><LF>

№	Field/Parameter	Description
	$	Sentence start ‘$’
	P	Proprietary sentence
	TNT	Proprietery code ID
	6	Идентификатор сообщения
1	Action ID	Service action ID (see 3.4.)
2	Reserved	Reserved, should always be ‘00’
	*	NMEA checksum separator
	hh	NMEA checksum
	<CR><LF>	end of sentence

2.7. IC_H2D_REM_SEND

Send a code message to a remote device.

Format: $PTNT8,x,x*hh<CR><LF>

№	Field/Parameter	Description
	$	Sentence start ‘$’
	P	Proprietary sentence
	TNT	Proprietery code ID
8	Sentence ID
1	Subscriber ID	Remote device ID (from 0 to 25. 25 is broadcast address)
2	Message ID	Code message ID (see 3.5.)
	*	NMEA checksum separator
	hh	NMEA checksum
	<CR><LF>	end of sentence

2.8. IC_H2D_REM_PING

Send a ping to a remote device.

Format: $PTNTA,x,x*hh<CR><LF>

№	Field/Parameter	Description
	$	Sentence start ‘$’
	P	Proprietary sentence
	TNT	Proprietery code ID
	A	Sentence ID
1	Subscriber ID	Remote device address from 0 to 24
2	Timeout	Max. timeout in msec (integer value)
	*	NMEA checksum separator
	hh	NMEA checksum
	<CR><LF>	end of sentence

2.9. IC_H2D_REM_PINGEX

Send a ping to a remote device (extended version).

Format: $PTNTE,x,x*hh<CR><LF>

№	Field/Parameter	Description
	$	Sentence start ‘$’
	P	Proprietary sentence
	TNT	Proprietery code ID
	E	Sentence ID
1	Subscriber ID	Remote device address from 0 to 24
2	Message ID	Requested parameter identifier (see 3.5.)
3	Timeout	Max. timeout in msec (integer value)
	*	NMEA checksum separator
	hh	NMEA checksum
	<CR><LF>	end of sentence

2.10. IC_D2H_REM_RECEIVED

Received a code message from a remote subscriber.

Format: $PTNT9,x,x.x,x.x*hh<CR><LF>

№	Field/Parameter	Description
	$	Sentence start ‘$’
	P	Proprietary sentence
	TNT	Proprietery code ID
	9	Sentence ID
1	Message ID	Received message ID (see 3.5.)
2	MSR	Signal quality (Main lobe to side-peak ratio, dB
3	Dpl	Doppler shift, Hz
	*	NMEA checksum separator
	hh	NMEA checksum
	<CR><LF>	end of sentence

2.11. IC_D2H_REM_TOUT

Remote device timeout exceeded.

Format: $PTNTB,x*hh<CR><LF>

№	Field/Parameter	Description
	$	Sentence start ‘$’
	P	Proprietary sentence
	TNT	Proprietery code ID
	B	Sentence ID
1	Subscriber ID	Remote device identifier
	*	NMEA checksum separator
	hh	NMEA checksum
	<CR><LF>	end of sentence

2.12. IC_D2H_REM_PONG

Remote device response received for request REM_PING.

Format: $PTNTC,x,x.x,x.x,x.x,x.x,x.x,x.x*hh<CR><LF>

№	Field/Parameter	Description
	$	Sentence start ‘$’
	P	Proprietary sentence
	TNT	Proprietery code ID
	C	Sentence ID
1	Subscriber ID	Remote device ID
2	MSR	Signal quality (Main lobe to side-peak ratio), dB
3	Dpl	Doppler shift, Hz
4	pTime	Signal propagation time to the requested device, sec
5	Dist	Distance to the requested device, m (only for devices with built-in depth sensor)
6	Dpt	Own depth, m (only for devices with built-in depth sensor)
7	Tmp	Water temperature, °С (only for devices with built-in depth sensor)
	*	NMEA checksum separator
	hh	NMEA checksum
	<CR><LF>	end of sentence

2.13. IC_D2H_REM_PONGEX

Remote device response received for request REM_PINGEX.

Format: $PTNTD,x,x,x.x,x.x,x.x,x.x,x.x,x.x,x.x*hh<CR><LF>

№	Field/Parameter	Description
	$	Sentence start ‘$’
	P	Proprietary sentence
	TNT	Proprietery code ID
	D	Sentence ID
1	Subscriber ID	Remote device ID
2	Requested data ID	Requested parameter ID (see 3.5.)
3	Requested data	Received value
4	MSR	Signal quality (Main lobe to side-peak ratio), dB
5	Dpl	Doppler shift, Hz
6	pTime	Signal propagation time to the requested device, sec
7	Dist	Distance to the requested device, m (only for devices with built-in depth sensor)
8	Dpt	Own depth, m (only for devices with built-in depth sensor)
9	Tmp	Water temperature, °С (only for devices with built-in depth sensor)
	*	NMEA checksum separator
	hh	NMEA checksum
	<CR><LF>	end of sentence

3. Identifiers

3.1. Device type identifiers

Value	Device type	Description
0	DEVICE_REDBASE	RedWave GIB
1	DEVICE_REDNODE	RedWave navigation receiver
2	DEVICE_REDNAV	RedWave diver’s navigation receiver
3	DEVICE_REDGTR	RedGTR code modem
10	DEVICE_REDLINE	RedLine modem

3.2. Error messages

Value	Name	Description
0	NO_ERROR	Request accepted
1	INVALID_SYNTAX	Syntax error in incoming sentence
2	UNSUPPORTED	Command is not supported
3	TRANSMITTER_BUSY	Transmitter is busy
4	ARGUMENT_OUT_OF_RANGE	One or more arguments in the sentence is out of range
5	INVALID_OPERATION	Operation cannot be performed at the moment
6	UNKNOWN_FIELD_ID	Unknown/unsupported field ID
7	VALUE_UNAVAILIBLE	Requested value is not available at the moment
8	RECEIVER_BUSY	Receiver if busy (waiting for a response of a remote device)

3.3. Local data identifiers

Value	Name	Description
0	DEVICE_INFO	Device information
1	MAX_REM_TOUT	Max. timeout value for remote requests, msec
2	MAX_SUBS	Max. number of addresses (device IDs)
3	PTS_PRESSURE	External hydrostatic pressure, mBar
4	PTS_TEMP	Water temperature, °С
5	PTS_DEPTH	Depth, m
6	CORE_TEMP	CPU core temperature, °С
7	BAT_VOLTAGE	Supply voltage, V
8	PRESSURE_RATING	Max. allowed external hydrostatic pressure, Bar
9	SURFACE_PRESSURE	Pressure at the water surface, mBar
10	WATER_DENSITY	Water density, kg/m3
11	SALINITY	Water salinity, PSU
12	SOUND_SPEED	Speed of sound, m/s
13	GRAVITY_ACC	Gravity acceleration, m/s2
14	Reserved
15	Reserved
16	Reserved
17	Reserved
18	Reserved
19	Reserved
20	SUB_ID	Device ID (address)

3.4. Service actions identifiers

Value	Name	Description
0	LOC_INVOKE_FLASH_WRITE	Save current settings in flash
1	LOC_INVOKE_DPT_ZERO_ADJUST	Set current pressure as the pressure at the water surface
2	LOC_INVOKE_RESTART	Hot system restart

3.5. Remote requests identifiers

Name	Value	Description
CDS_CMD_PING	0	Ping
CDS_CMD_PONG	1	Pong
CDS_CMD_DPT	2	Depth
CDS_CMD_TMP	3	Temperature
CDS_CMD_BAT	4	Supply voltage
CDS_CMD_USR_0	5	User command
CDS_CMD_USR_1	6	User command
CDS_CMD_USR_2	7	User command
CDS_CMD_USR_3	8	User command
CDS_CMD_USR_4	9	User command
CDS_CMD_USR_5	10	User command
CDS_CMD_USR_6	11	User command
CDS_CMD_USR_7	12	User command
CDS_CMD_USR_8	13	User command
CDS_CMD_USR_9	14	User command
CDS_CMD_USR_10	15	User command
CDS_CMD_USR_11	16	User command
CDS_CMD_USR_12	17	User command
CDS_CMD_USR_13	18	User command
CDS_CMD_USR_14	19	User command
CDS_CMD_USR_15	20	User command
CDS_CMD_USR_16	21	User command
CDS_CMD_USR_17	22	User command
CDS_CMD_USR_18	23	User command
CDS_CMD_USR_19	24	User command
CDS_CMD_USR_20	25	User command
CDS_CMD_USR_21	26	User command
CDS_CMD_USR_22	27	User command
CDS_CMD_USR_23	28	User command
CDS_CMD_USR_24	29	User command
CDS_CMD_USR_25	30	User command
CDS_CMD_USR_26	31	User command
CDS_CMD_USR_27	32	User command
CDS_CMD_USR_28	33	User command
CDS_CMD_USR_29	34	User command
CDS_CMD_USR_30	35	User command
CDS_CMD_USR_31	36	User command
CDS_CMD_USR_32	37	User command
CDS_CMD_USR_33	38	User command
CDS_CMD_USR_34	39	User command

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