In this presentation the electro-acoustic factors affecting the quality of telephone speech are shown to consist of: (1) Listening factors such as loudness, noise, and frequency shaping (2) talking factors such as echo and sidetone, and (3) conversational factors such as delay. Listening factors in particular are qualitatively interpreted in terms of the effect of telephone connection loss and frequency shaping on speech loudness at the ear relative to the hearing threshold, as well as the effect of noise on the hearing threshold. We then consider a typical telephone connection in which combinations of the above factors are manifested; this is done in the context of a hardware simulation facility used by BNR to simulate various telephone network impairments for the purposes of objective and subjective evaluation, and grade-of-service studies. Finally various grade-of-service results are presented pertaining to connection loudness loss and noise, talker and listener echo in conjunction with delay, and the subjective equivalence of continuous and speech correlated (quantization) noise.