xpxp2002 Yep. At one time when T-carrier and microwave links were the norm, sites were often connected in a hub-and-spoke configuration with a hub site typically using T3 circuits to bring everything back to the MSC.
In SFL AT&T Wireless/BellSouth Mobility used tons of T1’s back to the MTSO, VZ loved microwave which emulated DS3’s.
A couple of decades back in Broward I was put on a project titled fiber to the cell, at the time the only competitor was FP&L fiber which leased dark fiber from us and did their own backhaul using OPGW strung atop of their high voltage transmission towers.
The project had two purposes lower O&M and more bandwidth for the release of 3G, the conversion of all sites AT&T, T-Mobile, Metro took us almost 3 years.
Everything was based on 2 fibers transmit/receive back to our CO’s where it would be transported to each carrier.
It worked so well the trouble load dropped by 60% resulting in a technological force imbalance ,a fancy way of saying a lot of techs could take a buyout while those who remained behind where shuffled around to backfill the retires.
It was a time of turmoil combined with tranquility, a lot less OT., a lot less rotted copper work and for those of us who had volunteered to be trained in fiber, a lot more job security.
I can still remember a number of old hats claiming that fiber stuff and wireless is not for me, no sir it’s, never going to work because copper is king and always will be.
They found out the hard way they where totally wrong as they left the work center for the last time heading into the sunset for retirement.
Now it didn’t happen overnight Randal Stevenson named it Project 2000, the year he predicted copper would totally go away, well copper is still hanging on but the amount is so small it can barely be measured and when it needs to be maintained the company has discovered they have very few techs left who know how to repair it.
For AT&T fiber and wireless has become the new king of communications and there will be no looking back.
Heck I am not sure if we have MTSO’s with #4 switch’s in them anymore I think they have all gone IP based.