Grandstream GBX20 Extension Module

Grandstream GBX20 Extension Module, 20 Buttons, 40 Contacts, Black//supported by the GRP2615, GRP2624, GRP2650, GRP26704.3 inch (272x480) TFT color LCD20 per page (each module contains 2 pages, for up to 40 lines per module)Combine up 4 daisy-chained modules for 160 contacts/extensionsBLF, call park /pick-up, speed-dial, presence, intercom, voice conferencing transfer/forward and morehttps://www.grandstream.com/products/ip-voice-telephony/extension-modules/product/gbx20-extension-module