The command sends a packet with arbitrary data to the adapter. The adapter returns this packet back.
{
"cmd" : "srv.dev.linktest",
"data": "44673908046779d8F46789084467A90D44673908046779d8F46789084467A90D046779d8F46789084467A90D"
}
{
"res": 0,
"data": "44673908046779d8F46789084467A90D44673908046779d8F46789084467A90D046779d8F46789084467A90D"
}
{
"res": -448
}