Final answer:
The 'R' next to a frequency in a communication box stands for 'Repeater', which is a device that extends the range of communication systems by retransmitting signals on different frequencies.
Step-by-step explanation:
The letter R in a communication box next to a frequency typically stands for Repeater, which is a type of electronic device that receives a signal on one frequency and then retransmits it, often at a higher power, on another frequency. Repeaters are used to extend the range of communication systems, particularly in situations where direct communication between transceivers is impeded due to distance or physical obstructions.
Repeaters are commonly used in various communication systems, including amateur radio, public service radio, and sometimes in commercial sectors. The repeater's role is to improve communication clarity and extend the reach of radio devices by effectively bypassing the limitations imposed by terrain or the limited power of handheld radios.