The TS-905 is an Infrared Transmitter/Receiver of the Infrared Conference system. It can be mounted not only to the ceiling and wall but on the microphone stand.
The YW-1024 is a distributor that can work in the frequency range of 1.6 to 1000 MHz (except 50 to 70 MHz). Power passing type permits easy power supply.
TS-905 A1 consist of TS-905 1 unit and YW-1024 1 unit.
