Mark and Dan,
Last year some of the ILECs closed the loophole on LADS or local area data services. This did not include all of the wire services used for alarm services, however.
Alarms services sometimes use individual conductors (as in when a pair goes bad, and a single surviving conductor can be used), or bad pairs which have been twisted together in order to provide a single conductor equivalency for ground signal returns, or sometimes they are McCullough variants, or they are 3002-type analog two wire and four wire data circuit assemblies that will pass analog data, etc. In short, there are a lot of alarm circuit types.
The problem with trying to get away with such a tactic as to use one of them for high speed data, though, is that there is no guarantee that it will work in the first place (assuming you can get the telco to provide you with a good, balanced pair with no bridged taps or loading coils, which is what s required) and even if it works initially, there is no incentive for the ILEC to fix it when it breaks, if d.c. continuity is maintained, or if it maintains its minimum set of parameter limits. And those limits are always far less demanding than those for DSL or other higher speed lines.
I once had a customer while I was Liaison between T and NYTel. He was using such lines in the downtown Wall Street area back in the Seventies. They were able to pass 9.6kbps and 19.2kbps data for about $40/month, using line drivers from Gandalf that cost them just under $300 ea, at a time when QAM and DPSK modems were going for about a dollar a bit. Translation, a 9.6 kbps or 19.2 diplexed modem from Codex or Racal at the time would have cost them $10,000 or $20,000 a pop, respectively. For both ends, that translates to a difference of $600 and $40,000 or an initial savings of $39,400 per site served.
You have to know that these guys running a service bureau (actually it was one of the first on line quote services -- Monchik Webber, anyone recall that name?) and they were happier than pigs in doodoo. They had a huge, absolutely HUMONGOUS, competitive advantage as a result of this technique.
One day they received a new line going uptown to DLJ, several CO hops away, and the darned thing wouldn't fly. After I investigated what had happened, I put them on to CSP type circuits. CSP stands for _c_customer _s_ervice, _p_rogram grade, and they are usually good up to 15 KHz for audio, and at the time, high speed facsimile services which used frequencies into that range. CSPs were like program grade stereo lines (PT, or Program Telephone lines) that tied into AM and FM radio stations, and connected said radio station studios to their transmitter and antenna sites out in the boon docks.
The newly installed CSP eventually worked like a charm for their line drivers in the same central office serving area, and even worked into adjacent COs and finally it worked into the DLJ scenario farther uptown. What eventually happened, though, is one day they had a trouble on the line, and the repair bureau changed a defective unloaded trunk pair to one that was "loaded."
When it still wouldn't work, the telco did a little investigatory work, and found that the customer was using the line for data services, and immediately yanked it out (plugged it off, was the term) and read them _and ME_ the riot act.
As an AT*T liaison to this Bellco (I was actually there as the hammer man from Mom, and I was supposed to ensure that things like this "didn't" happen!), I had little recourse but to sit and take it on the chin. The customer, however, was besides himself, because he had ordered a couple of dozen of these line drivers and was all set to tear up the streets of Manhattan with his new low-ball service. They had to change their strategy, as you can easily see.
Is there a moral to this story? You tell me.
FWIW, Frank C. |
