This receiver responds to the wireless RF signals sent by the following 200 series transmitters: Universal Transmitter (#7400) Motion Detector (#7402) Miniature Magnetic Contact Transmitter (#7414) Pendant Transmitter (#7416) 4 Button Transmitter (#7406) 2 Button Transmitter (#7405) The receiver has both normally open and normally closed terminals for each channel. The state of these terminals changes when it receives a signal from a transmitter, eg. the N/C contact becomes open and the N/O contact closes. When the signal stops, the contacts revert to the original state. A transistor output of 12V 25mA that can be connected to a supplied buzzer or other device becomes live when the battery low signal is received from a transmitter. A 12VDC power supply is required. Contacts are rated at 1A 24VAC/DC. Also available in 2-Channel and 1-Channel versions. One channel version does not have the battery low output.