Building-automation token-passing bus over RS-485. Has TWO independent CRCs in one frame: a header CRC and a separate data CRC -- and the data CRC is entirely absent when there's no data, not just zero-length.
Physical UART Transport (9600 bps, 8N1.0)
Send command DataFrame (ID: 0x00)
integrityCheck (CRC-8) covers the fixed header only. secondaryIntegrityCheck (CRC-16, presentWhen=when-data-present) covers data and is entirely absent -- not even a zero-length placeholder -- when length=0, e.g. a Poll-For-Master token-passing frame with no data field at all.
Available only on servers:
Accepts the following message:
integrityCheck (CRC-8) covers the fixed header only. secondaryIntegrityCheck (CRC-16, presentWhen=when-data-present) covers data and is entirely absent -- not even a zero-length placeholder -- when length=0, e.g. a Poll-For-Master token-passing frame with no data field at all.
{
"command_id": 0,
"frameType": 0,
"destinationAddress": 0,
"sourceAddress": 0,
"data": "string"
}
integrityCheck (CRC-8) covers the fixed header only. secondaryIntegrityCheck (CRC-16, presentWhen=when-data-present) covers data and is entirely absent -- not even a zero-length placeholder -- when length=0, e.g. a Poll-For-Master token-passing frame with no data field at all.