Hello,
I have a similar problem with my UCMGSM4 which stopped working all of a sudden after 9 years, without mains interruption or whatever known reason.
I get different status messages with different firmware versions which I tried in the process of diagnosing, such as:
GSM Network Strength 0 - no network
Unknown GSM module
Not supported by firmware
There is network coverage in the area. I have used two different SIM cards from two different operators which have been confirmed to work in other equipment and with disabled pin, without success.
Checked sim card pins on the board which are clean with spring action.
I have one antenna connected on the board.
On the main board LED RDY and BUSY1 D2 are solid on.
On the daughter board LED D4 is solid on and LED 3 is flashing
When dialling in with one of the cards that supports voice, sometimes it rings, but there is no answer from Comfort.
I have tried to update to firmware GSMA8.004 but has not been accepted by the module.
Any idea what else to try?
George
The UCMGSM4 module is 2G. The 2G network will never be switched off, as the network operators told me, because there are too many old modems relying on SMS messaging for machine communication.
As I said I tried a second SIM card from another operator without success.
I tried then both SIM cards from the two different network operators on another 2G modem and both cards are able send and receive SMS messages, so it is definitely not an issue of the GSM networks or SIM cards.
From the LEDs on the submodule, it appears that the modem is connected to the GSM network. This is confirmed also from the fact that the voice dial in is ringing sometimes with the voice enabled SIM card. The UCMGSM4 on the other hand is connected to Comfort as it is polling, and I can do software updates/downgrades on it.
Based on the above I tend to believe that there is intercommunication problem between the two boards. Please let me know how to check that and what else I can do.
What is the name on the square gsm module, eg SIM7600E, SIM5350, TC35 etc? It may be displayed in GSM properties depending on how old the module is.
Busy 1 LED permanently ON means that there was an eror in a received me4ssage from the GSM. Normally BUSY1 should blink when there is a message from the submodule and BUSY2 should blink when there is a message to the module eg send sms. I suspect thatsaince it suddenly stopped working a few weeks ago that the GSM submodule may be faulty
did you upgrade the GSM4 firmware recently?. your firmware is GSM 8.240 which was released in august 2024. Your gsm module is SIM900, a 2G module. The possibility is that GSM 7.240 does not work for SIM 900 anymore. As we do not have a 2G network (since the last 5 to 10 years) we cannot even test for 2G in production. Do you remember that previous firmware? If so downgrade to that version, and your module may work again
