GBX20 and GRP2634


Good afternoon!

Does the GRP2634 model support the GBX20 Extension board ?

After connecting, the extension board displays the message “connecting…”

Firmware version
GBX20 -
GRP2634 - (Prog)


The spec sheets for the GRP2634 and GBX20 do not indicate that either device is compatible with the other.


The GBX20 is an Extension Module that adds functionality, versatility and flexibility to Grandstream’s GRP2615 and GRP2624 Carrier-Grade IP Phone’s and the GXV3350 IP Video Phone. It features a 272x480 LCD display that offers up to 40 contacts per module with support for up to 160 contact s by using 4 modules. The GBX20 supports a wide-range of advanced call features including BLF, call park /pick-up, speed-dial, presence, intercom, voice conferencing transfer/forward and much more. An ideal solution for businesses and receptionists managing high call volumes, the GBX20 ensures maximum productivity by efficiently monitoring and dispatching incoming calls.