Which item is listed as a UL signaling option that is described as a transmitter?

• A. Direct wire
• B. McCulloh transmitter
• C. Multiplex digital arm communicator
• D. One way radio

Answer: (B)

The key idea here is understanding what UL calls a signaling option versus a signaling path. A transmitter is something that actively sends the alarm signal to the central station. A direct wire is just the physical wiring path; it doesn’t itself transmit signals, it carries them to the control panel. A multiplex digital arm communicator is a digital signaling device described as a communicator, not specifically as a transmitter. One-way radio is a signaling method using radio, but UL labels it as a radio signaling option rather than a standalone transmitter. The item that UL lists as a signaling option described as a transmitter is the McCulloh transmitter, which specifically fits the idea of a device that emits the alarm signal to the monitoring station.