The Grandstream GXP2200EXT is a backlit LCD extension module featuring 20 dual‑color programmable keys and 2 arrow navigation keys for paging — expanding call control, BLF, speed dial, and presence monitoring on supported Grandstream IP phones. Each module supports up to 40 contacts (with paging) and can be daisy‑chained (up to 4) for up to 160 contacts/extensions — ideal for receptionists, executives, and high‑call‑volume users.