Here is how it works: You make a phone call. It runs down to the local switch, then over to the CO. The CO sits at a node on the internal telephone company network. The call, which by this time has been converted from analog to digital, is then passed to equipment that breaks it into hunks of data that is then transmitted over the fiber. This can be done via ATM (Asynchrous Transfer Mode) or good old Ethernet. The data bangs along through more central nodes (like the one described above) then gets converted back into information that the person you are calling's phone can understand. I am certain that there are good old fashioned copper line technologies still rattling along (until relatively recently, South Knoxville was crippled with bad old switching devices at the neighborhood level), but most of it runs along on the backbone that these companies invested so much into in the late 80s and through the 90s. The commercial Intarweb uses the same data transmission paths. It would be stupid to duplicate it.*

This isn't correct, Metulj.

Interoffice transport is done via optical, but the bandwidth isn't shared between regulated service (i.e. telephone) and deregulated (i.e. Internet) service.

(1) Not all Central Offices are equipped for Internet service. (2) There are still some analog-only offices out there (if you look in a Telcorida LERG you may see some 1AESS facilities, e.g.; I know of one in metro Nashville, for that matter). (3) Bells couldn't carry Internet traffic over the same fiber which carries phone service because of equal access provisions -- if they carried that traffic themselves, they'd have to let every other carrier have access to it. This is a regulatory regime called "parity." (4) If the Internet was carried on common facilities with phone service, your telephone would go down any time that there's a cable fade on Internet service or a routing issue, etc. and you couldn't guarantee quality of service end to end because of "net neutrality" provisions anyway.

I mean, theoretically, sure -- but the Baby Bells up until recently weren't even allowed to carry traffic across LATA boundaries. It may be "stupid" to duplicate services but that's what you had to live with after the 1982 modified final judgment (which broke up AT&T) and before the 1996 Telecom Act, which only allowed Bell Operating Companies to carry LD traffic once they'd met a fairly strict set of "relief" criteria. Tariffs and regulation have made sure that the plumbing is separate. Usually phone and data are in separate rights of way and separate conduit, let alone on separate fiber strands.

(At UT, I'm pretty sure that they have an OC-48 which is co-lo with Bell at KNVLTNMA, but UT provides its own optical muxes. They're not even mixing traffic on the same SONET facility -- they're aggregating that traffic off OC12/OC3 channels but pass it off to different facilities at the CO. Some is on the big UT Siemens switch and provides SS7 to the UT campus -- which, incidentally, is provided by US LEC, not Bell -- but the routes out of that OC48 are diverse for local, LD, and Internet. Not even Bell itself uses common facilities for Internet and voice among its 60,000 employees in its nine state region.)

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Wasabi peas are people! They're people!

It's best to just assume that all your communications (phone and internet) is being tracked.  The NSA has access to the communications backbone, along with massive data storage capability. 

Brian A.
I'd rather be cycling.