MeshCom 4.0 uses the AX.25 protocol for the payload data as defined for APRS. (aprs101.pdf APRS PROTOCOL REFERENCE Version 1.0 2000, Page 12)
Find use:
- Identifier - APRS data type identifier
- Message ID - 32-bit LSB->MSB unique value
- MAX-HOP - max. 7 (mask 0x07) default 5 is used which allows 4 more passes.
- 0x80 - Identifier whether this message has already run via MQTT server.
- 0x40 - Identifier that this message is to be supplemented per MeshClient with the callsign of the forwarding station. For measurement and control purposes.
- Source address - This field contains the callsign and SSID of the transmitting station.
- Destination Address - This field may contain an APRS destination callsign or "*" for transmissions to ALL.
- Digipeater - There can be 0 to 8 digipeater call signs in this field. Note: These digipeater addresses can be overwritten by a generic APRS digipeater path (specified by the SSID of the destination address).
- Information - This field contains transport data. The first character of this field is the APRS data type identifier, which indicates what type of data follows.
- Frame Check Sequence - The FCS is a sequence of 16 bits used to check the integrity of a received frame.
Messages:
Text messages:
:|!MMMMMM|!HH|OE0XXX-99|>*|:|Text message|!00|!HW|!MOD|FCS#
Text messages with Path from Mesh:
:|!MMMMMM|!HH|OE0XXX-99,OE3XXX-12,OE3YY-12|>*|:|Text message|!00|!HW|!MOD|FCS#
Position messages:
!|!MMMMMM|!HH|OE0XXX-99|>*|!|4800.00|N|/|01600.00|E|#| BBB /A=HHHH|!00|!HW|!MOD|FCS#
Checksum: FCS is formed as an unsigned 16-bit sum of the protocol bytes 0 to incl. MOD byte and little endian is appended after the MOD byte.
Legend:
Protocol elements:
| ... is only used to show the separations here in the text
Message elements
Short code Field name Variable type : ! Message identifier Version 4.0 MMMMMM Message ID 32-bit LSB->MSB HH MAX-HOP 8-bit bit mask 0x07 Message via MQTT server Bit mask 0x80 Insert path in mesh (with comma as separator) Bit mask 0x40 4800.00 Latitude Degree/decimal x 100 01600.00 Longidude Degree/decimal x 100 N N ord / S outh char / APRS SYMBOL group (/ or \) char E E ast / W est char # APRS SYMBOL char BBB Battery status in % int 0 - 100 /A=HHH GPS sea level (m) int 0 - 40000 PqayLoad completion closes the APRS PayLoad range 0x00 HW Hardware ID (see extra table) 8-bit (see table) MOD LoRa Modulation ID (MediumSlow...3) 8-bit (see table) FCS# Checksum incl. identifier and 0x00 from message completion 32-bit LSB->MSB
MeshCom hardware
Hardware ID HW Type MCU Type LoRa type HW abbreviation HW version 1 TTGO ESP32 Paxcounter ESP32 SX1278 TLORA V2 2 TTGO ESP32 Paxcounter ESP32 SX1278 TLORA V1 3 TTGO ESP32 Paxcounter ESP32 SX1278 TLORA V2 1.6 4 TTGO T-Beam ESP32 SX1278 T-BEAM 1.1 5 TTGO T-Beam ESP32 SX1268 T-BEAM-1268 1.1 1268 6 TTGO T-Beam ESP32 SX1262 T-BEAM-0.7 0.7 7 T-Echo LoRa SX1262 nRF SX1262 T-ECHO 8 T-Deck ESP32-S3 SX1262 T-DECK 9 Wisblock RAK4631 nRF Wisblock nRF RAK4631 10 WiFi LoRa 32 v2 ESP32 SX1262 HELTEC-V2-1 V2 11 WiFi LoRa 32 v1 ESP32 SX1276 HELTEC-V1 V1 12 TTGO T-Beam ESP32 SX1278 TBEAM-AXP2101 39 Ebyte Lora E22 ESP32 SX1278 EBYTE-E22 43 WiFi LoRa 32 v3 ESP32-S3 SX1262 HELTEC-V3 V3
MeshCom modulations
MOD ID Transmission range Planned range (km) Transmission speed Parameter 0 Extended range 10-20 fast 1 Extended range 10-20 slow (robust) 0.275 kbps 2 Additional extended range 20-40 slow (robust) 0.183 kbps 3 Normal range 5-10 slow (robust) 4 Normal range 5-10 fast 5.469 kbps 5 Local area 0-5 slow (robust) 6 Local area 0-5 fast 21.875 kbps
Message elements
| Short code | Field name | Variable type |
|---|---|---|
| : ! | Message identifier | Version 4.0 |
| MMMMMM | Message ID | 32-bit LSB->MSB |
| HH | MAX-HOP | 8-bit bit mask 0x07 |
| Message via MQTT server | Bit mask 0x80 | |
| Insert path in mesh (with comma as separator) | Bit mask 0x40 | |
| 4800.00 | Latitude | Degree/decimal x 100 |
| 01600.00 | Longidude | Degree/decimal x 100 |
| N | N ord / S outh | char |
| / | APRS SYMBOL group (/ or \) | char |
| E | E ast / W est | char |
| # | APRS SYMBOL | char |
| BBB | Battery status in % | int 0 - 100 |
| /A=HHH | GPS sea level (m) | int 0 - 40000 |
| PqayLoad completion | closes the APRS PayLoad range | 0x00 |
| HW | Hardware ID (see extra table) | 8-bit (see table) |
| MOD | LoRa Modulation ID (MediumSlow...3) | 8-bit (see table) |
| FCS# | Checksum incl. identifier and 0x00 from message completion | 32-bit LSB->MSB |
MeshCom hardware
| Hardware ID | HW Type | MCU Type | LoRa type | HW abbreviation | HW version |
|---|---|---|---|---|---|
| 1 | TTGO ESP32 Paxcounter | ESP32 | SX1278 | TLORA | V2 |
| 2 | TTGO ESP32 Paxcounter | ESP32 | SX1278 | TLORA | V1 |
| 3 | TTGO ESP32 Paxcounter | ESP32 | SX1278 | TLORA | V2 1.6 |
| 4 | TTGO T-Beam | ESP32 | SX1278 | T-BEAM | 1.1 |
| 5 | TTGO T-Beam | ESP32 | SX1268 | T-BEAM-1268 | 1.1 1268 |
| 6 | TTGO T-Beam | ESP32 | SX1262 | T-BEAM-0.7 | 0.7 |
| 7 | T-Echo LoRa SX1262 | nRF | SX1262 | T-ECHO | |
| 8 | T-Deck | ESP32-S3 | SX1262 | T-DECK | |
| 9 | Wisblock RAK4631 | nRF | Wisblock nRF | RAK4631 | |
| 10 | WiFi LoRa 32 v2 | ESP32 | SX1262 | HELTEC-V2-1 | V2 |
| 11 | WiFi LoRa 32 v1 | ESP32 | SX1276 | HELTEC-V1 | V1 |
| 12 | TTGO T-Beam | ESP32 | SX1278 | TBEAM-AXP2101 | |
| 39 | Ebyte Lora E22 | ESP32 | SX1278 | EBYTE-E22 | |
| 43 | WiFi LoRa 32 v3 | ESP32-S3 | SX1262 | HELTEC-V3 | V3 |
MeshCom modulations
| MOD ID | Transmission range | Planned range (km) | Transmission speed | Parameter |
|---|---|---|---|---|
| 0 | Extended range | 10-20 | fast | |
| 1 | Extended range | 10-20 | slow (robust) | 0.275 kbps |
| 2 | Additional extended range | 20-40 | slow (robust) | 0.183 kbps |
| 3 | Normal range | 5-10 | slow (robust) | |
| 4 | Normal range | 5-10 | fast | 5.469 kbps |
| 5 | Local area | 0-5 | slow (robust) | |
| 6 | Local area | 0-5 | fast | 21.875 kbps |