The JF-2SD is the audio only sub station for the JF series video entry security system. The JF system will support 2 video doors stations and 3 inside color monitor stations (1 master monitor and 2 subs).The JF series has a built in picture memory feature that can be set to record automatically when the visitor calls, or the record can be done manually by the user. Up to 50 images can be recorded at a rate of 1 frame per second and 8 frames per image (400 total frames). Up to 10 images (80 frames) can be saved and protected from automatic overwriting. From the JF-2SD you can answer the call from either door station, communicate with the visitor, and release the door. The JF-2SD can also place an all call to the other monitors/subs in the system.The JF-2SD has an adjustment for the receive volume and an adjustment for the Chime Tone volume.