- 38 programmable keys each with a dual-color LED - Daisy-chain 6 modules for 228 programmable keys - Dual color (red or green) LEDs for line status information - Supports Busy Lamp Field(BLF), Bridge Line Appearance(BLA) - Programmable for speed dialing, call pickup, Intercom,hold, transfer, voicemail, forward, DND... - Applies to Yealink IP Phone SIP-T28P and SIP-T26P - Expansion module( <2) is powered by the host phone