Ring A Ding
By stern on Jul 31, 2005
A few hundred feet of Cat 5, RG59 coax and some AWG 14 later, I had gotten the basic "communications board" down to the bare minimum: 2 12-port Cat 3 panels for phones, 6 RG6 feeds for digital cable sets and cable modem, and two spare phone jacks for the alarm system and for the telephone/doorbell interface (so when you ring the doorbell, the phones ring, and you can talk to the person at the door via the phone, rather than the hoot and holler method).
Cutting the wires and removing old home communications toys was easy. Finding out which lines ran where was more challenging, but it let me use my latest toy: a Resi-Toner TG400, a home-quality line ringer for the weekend cabling warrior. Identifying the twisty maze of beige phone cables, all alike, wasn't too hard. I popped the Resi-Toner into the wall jack I was trying to trace back. In "tone" mode, it sends a warbling tone down the line; I then retreated back to the basement where I had a regular telephone handset, substituting an alligator-clip cord for the regular telephone line cord. Ringing out the line then required little more than clipping onto successive leads from each line until I heard the phone warbling back at me.
Something so obvious has to have a catch. I decided to start with the room furthest from the utility closet, thinking that the trips up (and down) two flights of stairs would be decidedly less fun when I was on the last line than just starting out. But after testing all 14 pairs of telephone lines, I couldn't identify the first room I had chosen. Fine, I thought, I'll RTFM; and sure enough when you use the Resi-Toner's RJ-11 output, it only sends tones on the "line 2" pair (orange/orange-white if you're a telco geek). I dealt with that curveball with a bit of brute-force engineering -- I twisted all three lines together while testing them, just in case one of the jacks was cross-wired and had line 2 on the line 1 pair.
Expecting to breeze through a dozen room excursions, I went right back to my homebrew 3-ring circus. Tested all dirty dozen lines, again, this time checking for warble on all three pairs in parallel. No tones. Foiled again. As my grandmother would say, gornisht. Not just nothing, but you're tired and you have nothing to show for it.
Back to my starting point. Unplug the Resi-Toner. The short RJ-11 cable I'm using as the veritable head end of my testing network looks old -- probably something I salvaged from one of four previous house moves. I hold it up to the light -- sure enough -- it's only a two-conductor cable, carrying one line (and definitely not line 2). So my Resi-Toner is warbling, but as I later explain, "I had an infinite impedance problem". "Didn't plug it in" is more accurate, but lacks engineering authority.
New RJ-11 jumper cable from Resi-Toner to wall jack. Three pairs in parallel. I get warbles on the 2nd pair I check, wrap a nice line label around it, punch it down in my new distribution block, and write the room location on the wall next to the block. Quick sprint upstairs, move the Resi-Toner, downstairs, repeat. Once I spent the first hour figuring out why I wasn't ringing anything, I ring out the 11 phone jacks and a doorbell in about half an hour.
Next projects: wireless 802.11g distribution, new cable TV runs, and chasing down the home speaker distribution system that has a few cables that appear headed to nowhere in particular. And I get to do all of this while dealing with a work-move impedance problem.