Multi-IMSI SIM card support on HL modems

We are looking at support for using Multi-IMSI SIM cards with the HL and WP series of modems. Currently when running with SIM cards from Twilio we are seeing two issues:

  1. The modem was registering on the network, and getting an IP address (verified via AT commands), yet the Android driver was indicating a successful registration but NO IP address.
  2. The driver is not able to switch from the default profile to a different IMSI profile resulting in a connection not getting established. The Android driver keeps resetting when it receives a request for a profile switch.



So point 1 is not going to have anything to do with the IMSI switching, thats going to be down to the Android system and its propagation of IP information through the system.

Re point 2, you have not specified a modem and the differences are quite big on several levels, as a bench mark I would use an appropriate WP modem as that has the most implemented from the chipset manufacturer to ensure compatibility. After that it gets complicated with log files and trying to understand how the SIM provider is triggering the IMSI switch i.e. through an applet running on the SIM, active connection with a server, etc?