RitronTSW16A Teleswitch System.  Excellent condition.  Operates with any radio transmitter and receiver. Includes Teleswitch transmitter and receiver.  Capable of remotely monitoring16 channels N/O or N/C contacts, latched or momentary over any radio system capable of voice frequencies.  Provides an open or closed relay for each channel.   Ideal for remote site alarms, etc. Operates on 12VDC.   Teleswitch transmitter connects to audio input on associated transmitter and receiver connects to audio output of associated receiver.   Will also operate over a telephone line or just a single conductor shielded cable. Maintenance manual included. $279. OBO   Shipping $38.00