Typical messaging flow:
1. User queues a message to be sent with application ID
40
, with a hold duration 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 outgoing
message queue. Message is given the message ID of
5354468575855
. The outgoing message
queue provides for a maximum storage of 1024 unsent messages. The outgoing message
queue is non-volatile, and messages persist through sleep mode and power cycling:
$TD OK,5354468575855*2a
3. If the message has not expired due to time (it was previously set to be held until 2 hours from
when it was entered), when the device hears a satellite pass overhead it attempts to send any
messages in its outgoing queue. Messages are scheduled to be sent in the order they were
entered into the device (e.g. first in outgoing queue, 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. The acknowledged message is marked in the outgoing message queue for deletion by the
device. Any unsent messages will be attempted to be sent by the device at a later time.
© 2022 SWARM TECHNOLOGIES
SWARM M138 MODEM PRODUCT MANUAL · REV 1.20 · FEBRUARY 2022
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78
