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#1 2015-09-19 15:44:21

jt
Member
From: Bermuda Triangle, NC USA
Registered: 2014-05-21
Posts: 1,470

Ethernet over (Cell Phone cut) POTS infrastructure?

From another thread:

jt wrote:

In a small shop or in the home, PhoneNet was the bombe. Its greatest unsung attribute/designed in feature was its being set up for the unused pair of the four pair-two line TelCo infrastructure available in every home and small, single phone line office in America!

IIRC, 10bT only uses four of the eight lines available on the cable/RJ-45 connector?

That equates nicely with the two pair wiring implemented in every (almost every?) phone installation. In the home of any cell only user, this twisted pair, solid copper infrastructure is made available to those users who's cut the umbilical cord to Ma Bell.

Is it possible to set up a small network using POTS lines for Ethernet routers/AppleTalk bridges?

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#2 2015-09-19 16:08:37

bbraun
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Registered: 2014-05-29
Posts: 1,064
Website

Re: Ethernet over (Cell Phone cut) POTS infrastructure?

POTS comes in a variety of flavors for 2 wire to 6 wire rj11's.
Telephone lines only use 1 pair, so many telephone wires are just 2 wire and won't work for anything useful.
4 wire will work for phonenet just fine without any modification.  To use it with ethernet, you need different ends.  You can't just plug the rj11 into an rj45 plug and have it work with ethernet.  You can either cut the ends off and crimp on rj45 connectors in the proper pinout, or you could try to make up some adapter.
And of course, don't cross the streams.  Don't connect a live telephone line to either phonenet or ethernet gear.  Or phonenet to ethernet.    Or vice versa.

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#3 2015-09-19 17:08:27

jt
Member
From: Bermuda Triangle, NC USA
Registered: 2014-05-21
Posts: 1,470

Re: Ethernet over (Cell Phone cut) POTS infrastructure?

Interesting, I've never seen a single pair installation in a home or office. I have seen just a single pair in the box at the point of entry, but not in a home or office's wiring from to room. If it's possible at all, noodling out the adaptation would be the point of this thread.

Questions:

Will Ethernet work over 2 Pair twisted copper lines over in-home distances?
Will the unused wiring reaching past one of the hubs need to be disconnected? I'm guessing so.
Will wiring a surface mount RJ-45 receptacle's terminals to the four terminal inside the TelCo two pair box in each room work to connect a pair of routers?

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#4 2015-09-19 18:12:30

Eudimorphodon
Member
Registered: 2014-09-02
Posts: 525

Re: Ethernet over (Cell Phone cut) POTS infrastructure?

I did a really half-***ed ethernet wiring job on an office back in... 97?, and, well:

1: Category 3 wiring (standard for phone installations since the... 1970s?) with four wires will do for 10baseT ethernet. For that matter barbed wire might do for 10bt if you insulate it. If you have a building with that sort of wire present *and the phone service disconnected* you can convert it to ethernet, just make sure you've separated all the lines at the telco box; you want everything to be point-to-point without a big "tail" hanging off. (In principle I suppose you could put a cheap hub outside in the junction box and tie all the legs to it to make a network...)

2: If your wiring topology isn't a "star", if you have a run of cable that has multiple junction boxes daisy-chained along it then that is likely to a problem. Any intermediate boxes between two points are going to introduce noise and echos. In principle I suppose you could use the wire between any two points to wire two devices together (as crossovers) but you'll have to "prune the tree". Every time there's a junction it should be punched down in either a jack or a proper terminal block: winding wires around screws won't be cool.

3: If you want better than 10bt you'll need better wire than the typical phone cable you'll find in an older house. Cat5 twisted pair is specified for 100bTX; I've done some *sort* of skanky things that weren't up to code and run 100 over it anyway, but your mileage may vary. 1000bt is right out, it requires all four pairs. (At a signalling level it's completely different than 10/100bt.)


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