gCore POTS shield / weeBell

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The gCore POTS shield is an expansion board for gCore. It contains a codec and a ringing Subscriber Line Interface Circuit (SLIC) for 2-line 600-ohm POTS (Plain Old Telephone Service) telephones. With gCore it is used to create weeBell, a personal telephone exchange (technically a Foreign Exchange Service or FXS device). Different firmware running on the gCore allows weeBell to enable use of old school rotary and DTMF telephones with a cellphone via Bluetooth or as a VOIP devices using the SIP protocol or even as a prop or installation controller allowing people to hear and leave recordings via a telephone. The weeBell project is documented on hackaday.io.

The gCore POTS shield, along with pre-programmed gCore boards, can be found on tindie.


  • Generates -48VDC line bias
  • Generates ring voltages
  • Detects off-hook and on-hook conditions
  • Supports rotary and DTMF dialing
  • Supports audio via 16-bit I2S codec
  • Supports Caller ID generation


  • Bluetooth Handsfree telephone service
  • SIP-based VOIP telephone service
  • Prop and Installation telephone controller


  • gCore POTS shield github repository (includes 3D enclosure files)
  • weeBell_bluetooth repository - gCore firmware for Bluetooth handsfree

Pre-compiled firmware may be loaded onto gCore using the gCore Serial Loader program. The current firmware version is v1.1.

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3D printed enclosure
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