<data> is in the same format as the original $TD command accepts for message content
<msg_id> is assigned by the device, and is an unsigned 64-bit value comprised of the device
ID, a day of year counter, and a message of day counter. Responses that have a 0 as the
message ID indicate that the message has not been placed in the queue and therefore has no
ID. The value should be treated as a simple arbitrary number.
November 2021 Swarm M138 Modem Manual - Rev 1.00 57/77