Rolm 66993 RP600 KEO Keyboard Expansion Module (Refurbished)Key Features: Siemens Rolm RP600 Keyboard Expansion Module Povides more line appearances for increased call handling and productivity Add on module sidecar which adds 20 programmable keys with LEDs Adds 20 additional buttons for a max of 29 line appearances For use on all RP612 and RP624 Phones: For the RP612 it allows a total of 32 keys For the RP624 it allows a total of 44 keys Includes specialized connector