Aiphone MY-2CD is a master station for PanTilt Video Entry Security Intercom, which can incorporate up to 2 PanTilt video door stations and 3 monitor stations. It features a 4" CRT video monitor, hands-free audio, door release button, chime/pre-tone volume control, brightness and contrast controls, and internal calling and communication. It also has a built-in call extension speaker output, allowing you to add a remote chime tone. The system is designed for indoor use only and requires a specified power supply for proper operation.