John:

The only work that I ever did on this system was MAC work, as in station relocations at my family's office. Most of it was straight-forward except for the intercom code matrix. The first conductor was related to the first digit dialed and the second conductor was the second digit. The whole show rode upon the yellow pairs on the second binder coming out of the "KSU". Other than that, I don't remember it being much different from the general 1A2 architecture.

I never heard of any crosstalk issues, in fact the system that they had was pretty reliable. The interconnect that installed the system (practically unheard of in 1974) actually hired me to refurbish phones and clean the warehouse. I never saw a single card or set come back in as defective in the year that I worked there after school.

Years later, I took some of their extra sets and rigged them into my next employer's 1A2 equipment using the "T/R/A/L" concept and they behaved just fine.

Ed Vaughn, MBSWWYPBX