Description:CM500 digital I/O expansion box provides 3 input (2-pin) and 3 relay output (3-pin) connectors for various detectors and alarms/sirens connection for complete secure of your home and office.Features: Design for Compro PTZ IP camera Connect with various detectors, sirens and alarms 15-pin connectors: input (2-pin) x3, relay output (3-pin) x3 Box dimensions: 104 x 59 x 27 mm Connection cable length: 100 cm