I have problem with data connections (PDP / PDN) starting to fail using Twilio SIMs (ie TMO) in Canada.
The module works fine initially but the suddenly gets in a state where the PDP won’t activity. Because the Attach works, the module sits there unable to get a data connection.
Manufacturer: Sierra Wireless, Incorporated
Revision: SWI9X30C_02.30.01.01 r7792 CARMD-EV-FRMWR2 2018/07/13 02:24:52
ESN: 12802254084, 80226504
IMEI SV: 16
Current Time: 271 Temperature: 45
Reset Counter: 7 Mode: ONLINE
System mode: WCDMA PS state: Attached
WCDMA band: WCDMA 850
WCDMA channel: 4412
MM (CS) state: IDLE NORMAL SERVICE
WCDMA L1 state:L1M_PCH_SLEEP LAC: 2937 (10551)
RRC state: DISCONNECTED UTRAN Cell ID: 0DC2A7C1 (230860737)
RxM RSSI C0: -79 RxD RSSI C0: —
RxM RSSI C1: — RxD RSSI C1: —
+CME ERROR: unknown
Using the AT+CGACT=1,1 seems to return very quickly. It is as though the PDP Request was not sent to the network.
We debugged with TMO and they could see the Attach from the device but no data connection attempt.
Putting another SIM in the module seems to allow the condition to clear. We have hundreds of 7455 in field so swapping SIMs is not a real fix.
Do the 7455 have an internal state where it will block PDP attempts for a particular APN? Is there an AT command that could clear this condition?