The Merlin 22 Button BIS Speaker Telephone Model # 7309H 22Btn BIS with has Four Fixed-Feature Buttons with LED indicators: Message, Speakerphone, Hands-Free Answer on Intercom/Microphone make it possible to handle an influx of calls even as you perform other tasks. Fixed-Feature Buttons for Conference, Drop, Transfer, Hold and Recall. Hearing aid compatible. 22 Buttons with LED indicators for line appearances, Intercom and programmable features. Additional Jack for a General Purpose Adapter or Headset. Compatible with System 25, MERLIN and MERLIN LEGEND Systems.