The 2955/2957 Radio Communications Test Set is a comprehensive radio transceiver test unit which covers the frequency range from 400kHz to 1GHz that provides AM, FM, and Phase Modulation measurements. Built-in audio generator covering 50Hz to 15kHz. Built-in CRT display for all measurement details. Simple color coded keys. Built-in help facility. Independent tuning for one and two port duplex systems. Built-in AF distortion, S/N, and SINAD measurements. Selective calling tones encoder/decoder including sub-audible frequencies. Twin 8-digit counter display for measuring af & rf signals. Soft key menu driven control.