big ass rectifiers
big ass solid copper busbars
huge gauge copper cables going around a central office (google "telcoflex IV")
big DC breaker/fuse panels
specialized dc fuse panels for power distribution at the top of racks, using little tiny fuses
100% overhead steel ladder rack type cable trays, since your typical telco CO was never a raised floor type environment (UNLIKE legacy 1960s/1970s mainframe computer rooms), so all the power was kept accessible by a team of people working on stepladders.
The same general thing continues today in serious telco/ISP operations, with tech features to bring it into the modern era. The rectifiers are modular now, and there's also rectiverters. Monitoring is much better. People are moving rapidly away from wet cell 2V lead acid battery banks and AGM sealed lead acid stuff to LiFePo4 battery systems.
DC fuse panels can come with network-based monitoring, ability to turn on/off devices remotely.
equipment is a whole lot less power hungry now, a telco CO that has decommed a 5ESS will find itself with a ton of empty thermal and power budget.
when I say serious telco stuff is a lot less power hungry, it's by huge margins. randomly chosen example of radio transport equipment. For instance back in the day a powerful, very expensive point to point microwave radio system might be a full 42U rack, 800W in load, with waveguide going out to antennas on a roof. It would carry one, two or three DS3 equivalent of capacity (45 Mbps each).
now, that same telco might have a radio on its CO roof in the same microwave bands that is 1.3 Gbps FDD capacity, pure ethernet with a SFP+ fiber interface built into it, and the whole radio is a 40W electrical load. The radio is mounted directly on the antenna with some UV/IR resistant weatherproof 16 gauge DC power cable running down into the CO and plugged into a fuse panel.
Can you give me a link to this 1.3 gbps radio product? I have some Alcatel radios with waveguides on a licensed band that only do 50 megabit that I would upgrade if there was something that could get more bits out of the same bandwidth and towers.
Ceragon is one brand name. If you need to keep an entirely indoor unit radio in a rack with the existing waveguide it'll cost a little more, since that's a more rare configuration for new 4096QAM modulation radios.
The 1.3 Gbps full duplex capacity assumes dual linear H&V polarization simultaneously, and assumes an 80 MHz wide FDD channel split such as in the 11 GHz high/low band plan. If you're in FCC part 101 regulatory band territory, and what frequency your existing radios use and existing path, you might not have that capacity. You could have an existing 40 MHz wide channel which will be half the capacity.
If you have a 50 Mbps radio product it's also very likely you're in a single polarity so you would need to recoordinate the path (around $1500) entirely to get the same MHz in the opposite polarity.
I don't have a link handy (on my phone), but I was involved in installs of licensed Cambium 18Ghz radios last year that were pushing >1Gbps. PTP-800 was the model number, if memory serves.