The GBX20 is an Extension Module that adds functionality, versatility and flexibility to Grandstreams GRP2615 Carrier-Grade IP Phone and GXV3350 IP Video Phone. It features a 272x480 LCD display that offers up to 40 contacts per module with support for up to 160 contacts 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.