A genuine single shared data line, not just RTS/CTS omitted -- both sides' TX and RX are the same open-drain/tri-state pin, common on microcontroller debug or bootload pins wired for minimal pin count.
Physical UART Transport (115200 bps, 8N1.0)
Send command Ping (ID: 0x01)
Dispatch Ping frame to microcontroller over serial line
Available only on servers:
Accepts the following message:
Command payload for Ping
{
"command_id": 1,
"opcode": 1,
"reserved": "string"
}
Unsolicited telemetry message Pong (ID: 0x81)
Unsolicited telemetry message from device: Pong
Available only on servers:
Accepts the following message:
Device-initiated telemetry payload for Pong
{
"opcode": 129,
"reserved": "string"
}
Command payload for Ping
Device-initiated telemetry payload for Pong