GXP-2000 Expansion Module (EXT) features 56 fully programmable buttons (each with dual-color LED) when used with GXP2000. The GXP-2000EXT is connected to and controlled by the GXP-2000 via a short cable included with the expansion package.  The GXP-2000 supports speed dialing, call transfer/forward/pickup on each of the programmable buttons and BLF (Busy Lamp Field) and BLA (busy line answer).  Up to 2 GXP-2000EXT modules can be cascaded per GXP-2000, allowing 112 fully programmable phone extensions.