This transmitter works with both analog and digital TVs.  One transmitter is needed for each TV or audio source and simply hooks up to the back of the TV.  This device transmits the sounds of the TV to the receiver, which allows you to hear everything from your TV.  

For a Wireless 900MHz system you need to order 1 Transmitter for every TV and 1 Receiver and CSAFE Cable for each piece of cardio.  If the cardio equipment DOES NOT have a CSAFE Port (usually found on older equipment, or non commercial equipment) you need to order a 9-Volt receiver adapter and a long 98" CSAFE Cable.

The price listed is just for the Wireless 900MHz Single Channel 399Transmitter.