Application Documentation Radio reciever - used to communicate with Digitrax radio and IR throttles.   The UR91 is the radio/IR receiver unit. The UR91 looks similar to a UP5 and is mounted in the fascia of the layout. The UR91 is simply an addition to your existing LocoNet so no additional wiring is needed. The antennas are concealed under the layout. The UR91 will support approximately 10 radio throttles. Most layouts will need just one UR91 but in some large configurations a second unit may be needed to compensate for "dead" spots. This unit is also equipped for concurrent infrared operation using all Digitrax IR throttles. Radio Equipped & Infra-ready throttles will run on fully charged NiCad batteries for approximately 6-8 hours and on regular alkaline batteries for about 10-20 hours. Features: Cost effective tetherless operation! Can be added to any existing LocoNet system. Radio range of approx 300-ft diameter circle. Operates in the 900Mhz band. Multiple LocoNet ID’s allow multiple clubs to operate in close proximity at train shows. Infrared throttles are an inexpensive way to have tetherless control indoors. Equipped with powerful dual IR LED emitters for transmission reliability. Keyboard lock feature to prevent commands being sent by mistake. Safety Selection for problem free operation. Operations mode programming allows programming without plugging in to LocoNet.