[1] [2]   REF.7954   MONOCHANNEL TRANSMITTER 433 MHZ Transmitters or remote controls include a key-ring and run on a miniature 12 V battery. Radio frequency equipment for remote operation of door-open mechanism. These systems have a RECEIVER installed ...  REF.7956   BICHANNEL TRANSMITER 433MHz if the receiver is bichannel (we can use one channel to open a door and the second for another door or to drive any device such as connecting an alarm), in this case, TRANSMITTER selected shoul be ...