The Zetron Model 5 Communications Encoder is a compact low-cost desktop paging encoder for selective calling of two-tone and five-tone sequential pagers.

A 12-digit high-quality keypad allows for manual entry of pager codes. A four-digit display indicates the number of the pager being called. The pager number remains on the display after the paging sequence is complete, allowing immediate re-page without reentry of the pager number. Three LEDs indicate when the encoder is paging, transmitting, and when the microphone is open for the voice transmission to tone-and-voice pagers. The voice transmission can be made through the built-in electret microphone or through a normal desk microphone. The built-in microphone, which can also be used to make voice broadcasts over the transmitter, is equipped with automatic gain control for optimum voice pick-up.