Typical messaging flow:
1. User queues a message to be sent with application ID 40, with an expiry time of 7200
seconds (2 hours). The use of indexing parameters in the body of the message is
recommended to aid in message identification and sequencing:
$TD AI=40,HD=7200,"{"d":"Demo message","t":"2021-02-26 14:28:56","seq":"00015"}"*09
2. Device acknowledges receipt of message, and message enters into device’s internal
message database. Message is given the message ID of 5354468575855. Database has a
maximum amount of 2048 messages stored. Database is non-volaModem and messages
persist through sleep mode and power cycling:
$TD OK,5354468575855*2a
3. If the message has not expired due to time (as it was set to expire 2 hours from when it was
entered), when the device hears a satellite pass overhead it attempts to send any messages in
its database. Messages are scheduled to be sent in the order they were entered into the device
(e.g. first in database, first transmitted). Each message heard by the satellite is individually
acknowledged with a $TD SENT response - the acknowledged message is referred to by its
message ID (5354468575855)
$TD SENT,RSSI=-99,SNR=5,FDEV=32,5354468575855*6f
4. Acknowledged message in database is marked for deletion by device. Any unsent messages
will be attempted to be sent by the device at a later time.
November 2021 Swarm M138 Modem Manual - Rev 1.00 75/77
To Next Page
Loading...