Welcome to SwitchPi website! We are concentrate on bringing the Raspberry Pi to Asterisk VoIP communication world.
We are producing two modules, they are PiTDM and PiGSM.
The PiTDM provides a module which can support up to 4 FXS or FXO modules.
We would like you to update the PiTDM firmware to the new version which based on Raspbx or Digium official GUI, that will let you play PiTDM module by much more easily. You can get it by following this manual for Raspbx and this manual for Digium official GUI
The PiGSM provides a module which can support a quad-band GSM/GPRS, that is integrated a SIM800L module, that works on frequencies GSM850MHz, EGSM900MHz, DCS1800MHz and PCS1900MHz. That features GPRS multi-slot class 12/ class 10 (optional) and supports the GPRS coding schemes CS-1, CS-2, CS-3, and CS-4.