The Meridian Option M3904 professional telephone is a multi-line phone which supports up to 12 lines. The Meridian Option M3904 offers the largest display in its class - at 5 lines x 24 characters. The Nortel M3904 Meridian Option Professional features include a personal directory, call log, volume control, headset option, LED lights, message, call log and redial applications. The personal directory PC utility allows you to create a directory file of up to 100 names on your PC and download it directly to the phone. Two adapter slots are available to accommodate an analog terminal adapter and external alerter and recoding interface.