Operating system name and version: CentOS 6
Version of smsd: 3.1.3
Smsd installed from: package repository
Name and model of a modem / phone: Alcom
Interface: serial

Hi,

we have been using SMS server tools for a long time and are happy with it. We keep adding new modems with new SIM cards and things are running smoothly. I was wondering though if there was a way to use multiple phone numbers (MSISDN) with the same modem at the same time. The network operator can assign multiple MSISDNs to the same SIM card, but when we receive messages we don't know which number the message was sent to because the text file for received messages doesn't have a To: line.

Is there a specific reason for this? Is there a way to work around this?

It would be very convenient for us, since we could run multiple applications that only require incoming messages with different MSISDNs to run on the same modem.

Thanks a lot,
Georges

Currently multiple MSISDNs are not supported. To: line is missing, because Protocol Data Unit does not include that information.

I do not know if there are any workarounds available. I assume that there is not, and I cannot make any tests as multiple MSISDNs are not available here.

Hi Keke,

thanks a lot for the quick reply. Is there a way I could try and find out what information the modem transmits exactly (like a binary dump)? I remember having an old Nokia phone that could handle 2 MSISDNs on a single SIM so there must be a way of finding out. However, this may also depend on the firmware of the modem. This is the one we'd like to use by the way: http://www.kamosis.com/store/files/Data_Communication/Modem_gsm_gprs_quadri_band_sans_fil_genpro20e.pdf

If you could point me to the right place in the code to look for things, I could do some tests myself. I found this in smsd.c:
const char *HDR_From = "From:"; // Msg file input: informative, incoming message: senders address.

which makes me think that this field was at some point meant to appear in the incoming SMS file.

Thanks a lot,
Georges

You can use a global setting log_read_from_modem = yes to get a hex dump.

Usually in dual-SIM systems, proper AT command should be used to select the SIM. The command varies by devices and is not supported by SMSTools3. I assume that your SIM with two MSISDNs is a SIM with two virtual SIMs, and this may be different. As you wrote, you can receive messages from both MSISDNs without any special command.

"From:" header is in the incoming SMS file, and it tells the senders number. What you are missing is "To:" header, but this information is not available.

You could do the following test:

- Stop the smsd if it's running
- Using your handset, send a SMS to both MSISDNs
- Communicate with your device, like smsd -C GSM1
- Try the command AT+CMGL=4

It should list both messages, and now you can see if there is any information about the MSISDN.