I'm seeking data on early AT&T fiber systems aka Lightwave.
I know FT3 was 90.524 Mbps, and needed regenerators every 4-5 miles. I'm interested in a FT7 installation, circa 1987. How frequently would it have needed regenerators, and what kind of bit rates would it have had?
Further, was FT3 multimode glass usable on FT7? I can't find much on the fiber used; and wonder how long it was usable with upgraded equipment.
When did the OC hierarchy take over?