Extension Modules – GBX20 Product Description GBX204.3 inch (272×480) color LCD 20 per page (each module contains 2 pages, for up to 40 lines per module) Connect 4 modules for up to 160 contacts/extensions See also different: ATAs & Gateways – HT801 v2 – HT802 v2 Business Conferencing – GMD1208 IP PBX Solutions – CloudUCM GXP Series IP Phones – GXP1610(P)/GXP1615