Where is this cable installed? Could be companies who host high traffic websites, government offices, schools or a location might have a DS3 on the back end just for a "as needed" basis.
DS3 interconnect coaxial cable should always be a 75ohm cable. A 50ohm can be used but you'll have lower performance and depending on the length of the cable run a signal might not even appear. Generic requirements for central office coax cable defines 734 and 735 as being the cables used for this application. If you're looking into a coax cable you probably should also look for the GR-139-CORE as a specification.
The 734 cable has a larger conductor compared to the 735 and that'll help you on those longer cable runs, plus the cost difference ain't a big deal so I would splurge for it. The 734 is used for interconnect up to 450 feet.
Let's take a look at a Commscope 734 plenum cable from our YouTube channel.
If you're just starting your research on DS3 hopefully this post helped out and don't forget to share this post!
"By Mercy Salinas"