What is in a phone company cable?


Old 07-26-07, 09:31 AM
wgc is offline
Thread Starter
Join Date: Dec 2005
Location: New England
Posts: 362
What is in a phone company cable?

Out of curiosity, what wires and sizes make up a phone company cable?

On the way to work, I saw one of the Verizon trucks with a huge spool of cable that they were attaching to a bridge under construction. It's hard to tell from driving by, but it looked black and rubbery, and at least an inch in diameter. What is in a typical one of those?

I assume it's not FiOS: those seem to have an orange jacket. Although, I'm curious about that too. What's in a typical one of those cables (more detailed than "a bunch of fiber")?
Sponsored Links
Old 07-26-07, 09:48 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,533
Those cables have several hundred or thousand pairs of twisted copper wire; each pair being a local loop phone line that runs from a home or business to the phone company CO (Central Office). From the CO, modern fiber optic networks take over to route calls to their destinations, but this "last mile" is still run with twisted copper wires. Very few locations in the US have fiber optic availability directly to the customer premises.
Old 07-27-07, 09:42 AM
ddr is offline
Join Date: May 2006
Location: New York City
Posts: 133
I'm not sure about the main FIOS lines, but the ones run to a customer's home are about 3/8" x 1/4" -- but thats all jacket for protection and support. The fiber line itself (with its own insulation) is only about the diameter of a #18 wire and carries pulses of light to a converter box on the side of the house where the signal is converted to analog.
Old 07-28-07, 08:35 AM
Forum Topic Moderator
Join Date: Sep 2005
Location: USA
Posts: 4,284
It's hard to tell the difference between fiber and copper - since the outer jackets are similar. The best way to tell (around here at least) is at the boxes on the poles that the fiber goes into, the fiber is wrapped in an orange sleeve for protection. FIOS specific cable is about 5/8" diameter and has I believe about 32 individual fibers. Also, they all have messenger wires in them (steel wire that supports the cables across the spans between telephone poles).

For more information about FIOS than you probably ever wanted to know:

(It's interesting if you're into that kind of thing)

Old 07-31-07, 02:49 PM
wgc is offline
Thread Starter
Join Date: Dec 2005
Location: New England
Posts: 362

Thanks for the info. FiOS service came to my area a couple of months ago and I am considering it. Considering the differences led me to curiosity about what's out on the pole.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Display Modes