E-20B Door Phone (Indoor Use)

Model: E-20B-EWP The E-20B is  for in  door use. Standard C.O  telephone line trunk, allow two-way handsfree communication. Models are available in two different housings to better suit the application. When the “Call” button is pressed, the E-10A or E-20B will come off-hook and will remain off-hook until a CPC signal is detected, the programmed timeout has elapsed, a busy signal is detected, or the call goes silent, making the unit automatically disconnect.