Simtech in AT-command mode disconnects after 30 seconds (and then fails hard losing the modem completely)
Similar situation as in #144 (closed) and with the AT+CMER=0,0,0,0
workaround in place for that issue to be able to get a connection established at all.
I'm seeing an issue where the symptom is basically that on a clean boot the connection is successfully established, but then the connection gets disconnected after exactly 30 seconds and then MM goes on to try to recover it completely lost track of the modem and eventually kicks it out (marking it as invalid) so that it no longer shows up in mmcli -L
at all.
The cause seems to be found in the AT+CGDCONT
and the AT+CGACT
commands. Apparently my test modem had several PDP Contexts already defined so that CID 4 was found to be matching and used. The connection then gets established and after 30 seconds MM checks with AT+CGACT?
is CID 4 is now active but modem says only CID 1 is active and all others are inactive and thus assumes we're now disconnected.
It seems that the modem will always report state in CID 1 when using AT+CGACT?
so the obvious workaround I've tested was to erase all profiles with AT+CGDCONT=1
(etc) so that MM doesn't find any matching profile and adds the profile we want to use in CID 1. This works around the issue and the connection works as expected.