... or her service. They system consist of a transmitter (Numerical Keypad)for the caller and a display receiver for showing call ... , easily operateGroup calling, group cancellingCompatible with all the CS display LED and shift receiving main unitUSB with 5V power supply, can ... Coding Capacity: 200Reminding: DingDongSize: 225*165*40mm queuing paging system, numerical keypad and LED display receiver