sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services Telecom Service & Providers Unknown Circuit IDs

You must have contacted a repair/maintenance person, where I’m assuming the original poster contacted a business office. Different support systems availed between those two groups as well as a different level of… level of… uh… training.

Oh Jeff… Let’s fix you terminology a bit … the prefix is the two digit numeric preceding the circuit id. The “DHZA” would be the service code (DH) and the service code modifiers (ZA.)

This might work if you have the time to waste.
Try tracing out the pairs to the cable that brings them in from the street. write down the cable and pair information and keep it in your car. If you see a telco repair truck at another site or whatever, grab the guy/girl and beg them for info.
Chances are that someone can tell you who is paying for the pairs to get to your site.

It's the long way around, but it has worked for me once.