Skip to main content

TX - Text Message

Transfers text or escaped byte payloads between Antares and configured destination points.

Qualifiers​

  • S: send text message (>STX...<)
  • R: response/forwarded frame (>RTX...<)
  • Q: defined in legacy protocol references

Format​

Set:

>STX{A...}<

Response frame:

>RTX{A...}<

Where {A...} is the message body.

Message Body and Escaping​

  • Message body can include printable text.
  • Byte-like payloads can be encoded with \XX escape sequences (two hex digits).
  • \XX sequences are decoded back to raw bytes when sent to serial in PAD/HEX modes.
  • To transmit ;, >, or < safely inside payload data, send them escaped (\\3B, \\3E, \\3C).

Examples of escapes:

  • \3B -> ;
  • \3E -> >
  • \3C -> <
  • \5C -> \\
  • \0D -> carriage return
  • \0A -> line feed

Parser-Based Behavior​

Antares behavior depends on source and MDT mode:

  1. NORMAL_MODE and source is SOURCE_AIRCOM:
  • Antares forwards STX as RTX directly to RS-232.
  1. NORMAL_MODE and non-air source:
  • Antares extracts payload from >STX...<.
  • If normal-mode escape substitution is enabled, ; and > are escaped as \3B and \3E.
  • Final message is routed to configured destination points as an RTX frame.
  1. PAD_MODE or HEX_MODE:
  • Antares extracts payload and decodes \XX sequences.
  • Decoded bytes are sent to the serial port as raw data.

Limits and Validation​

  • Minimum valid command: >STX<.
  • Command must end with <, otherwise delimiter error.
  • Maximum command length is MAX_TEXT_MSG_LEN (1024 bytes) including delimiters.
  • Effective maximum payload is 1019 bytes (1024 - 5 for >STX and trailing <).

Examples​

Send plain text:

>STXHello world<
>RTXHello world<

Send escaped bytes:

>STX\02Test\03<
>RTX\02Test\03<

Send a semicolon and greater-than using escapes:

>STXValue\3BNext\3E<
>RTXValue\3BNext\3E<
  • MT configures MDT mode, routing, and packet criteria.
  • MTE configures the MDT escape-character behavior.
  • See Serial Port Devices for end-to-end serial data flow.