Same as the 655 Monitor Amplifier, but now has a sliding battery drawer! The dialer has the capability of storing 9 telephone numbers, a low battery light, built in microphone and defeatable ringer for incoming calls. To operate on the telephone line, use the RJ-11or 3pin XLR jack on the box. The XLR-3 on this model is for all audio input, wet or dry . A 25' telephone cord is included (MAT-2 Part #341).