From FB group Bell Telephone…
In the days of analog phones like 500s and 2500s, Ma Bell had the phone matched to the line, so whatever the line length was, it compensated and the signal levels were very uniform, it worked great.
Then came along the full duplex digital system, and everything went to hell. The signals were separated so if the levels were too high, there wasn’t a problem with feedback or howling. So whatever was too low or too high never got corrected. The result was there were constant complaints from the users that the volume was too high or low. And of course there was constant finger pointing because of different vendors and equipment. So nothing seems to have gotten much better, same with cellphones. 😣
