I am currently working on a project for which it is required to receive SMS messages using a dongle. The dongle being used is a Huawei E3131 Hi-Link dongle, which is configured in serial mode via USB-modeswitch. Communication to the dongle is done via AT-commands. The problem is that SMS messages are not being received. After alot of attempts to fix this I found that SMS messages are ony received after sending out an SMS on the dongle itself. I've also tested with another dongle (Huawei E173), but this works fine.
For testing purposes I am not using any code yet. I am manually execute the following AT-commands to initialize the dongle:
- Pin is ready according to "AT+CPIN?".
- Dongle is set to text mode via "AT+CMGF=1".
- SIM storage is used via "AT+CPMS="SM","SM","SM"".
- Message indicators (AT+CNMI) is set to "1,2", but "0,0,0,0,0" and other combinations have been tried as well.
After executing these commands I check the received SMS messages via "AT+CMGL" and none show up (as expected). Then I will send an SMS to the dongle. After waiting for a while still no messages show up (though you'd expect them to). Then I will use the dongle to send an SMS to another device via the AT+"CMGS" command. This SMS is correctly received on the other device. After sending this SMS suddenly the SMS sent to the dongle show up via "AT+CMGL".
I've read through the Huawei AT commands manual but have still no clue what's going on. I've excluded the following possible issues:
- According to "CFUN?" the dongle is in "Online" mode, like you'd expect.
- The SIM is not full as "AT+CPMS?" shows.
- Enabling mobile equipment errors does not produce any extra output ("AT+CMEE=2").
- CREG shows that we are registered (on a roaming network).
- CSQ shows a signal is available (strength of 16,99).
- I've tested with another E3131 dongle, but this produces the same problems.
- RSSI messages are still being received.
- Sometimes switching on the internet on the dongle produces the same result as sending out an SMS.
- In the SMS gateway which can be used for sending SMS, the SMS will stay in the "pending" state until the message is delivered in the storage on the dongle.
Does anyone know what's going on?