[Info-vax] US Broadband

[glen herrmannsfeldt]

Scott Dorsey <kludge at panix.com> wrote:

(snip, I wrote)

>>Yes, but as I understand it, not all telcos will lease such pairs.
 
> If it's in the tariff, they have to provide it.
 
>>It used to be that they were commonly used for burglar alarms (maybe
>>still) and that you could ask for one of those. 
 
> Okay, those are unconditioned dry copper pair circuits.  
> Those used to be the cheapest possible circuits, and you might be 
> able to run a T-1 over one for a short distance.

Yes. And if a short distance was enough, much cheaper than paying
for a T1 line.
 
> People used to use radio loops, unconditioned pairs, and voice-grade dry
> circuits (like the classic 48F 4-wire circuit) for cheap data back in the
> eighties.  For the most part, these circuit types either are no longer in
> the tariffs or they have been replaced in some way.
 
> For example, if you ordered a burglar alarm circuit back in the 
> eighties, you were apt to get direct copper continuity from end 
> to end, even though the tariff only guaranteed contact closure and 
> some insanely low signalling rate.
 
> If you order the same circuit under the same line item in the 
> tariff today, you will probably get a digital circuit that only 
> carries contact closure, nothing else, and you won't have any luck 
> putting wideband data on it.  

> If you order a 48F 4-wire voice circuit today, it will be digitized 
> and then undigitized somewhere between the two ends.
 
> The T-1 circuit is wideband and conditioned, and you pay for that.
 
>>Well, the case that I was interested in some years ago was where I would
>>use both ends of, say, a T1 link.  Maybe home to work, or something like
>>that.

>>As I understood it (again, some years ago) the school district could do
>>that to link schools to the central office, sometimes chaining through
>>schools to get there.  That was an upgrade from ISDN that they were
>>previously running.
 
> When you purchase a tariffed service, the telco has to meet the 
> performance and reliability specifications in the tariff.  
> When you order a burglar alarm circuit, the performance 
> specifications are pretty damn low.  In the distant past, 
> it was not unusual for the telco to greatly exceed the 
> specifications in the tariff just because of the nature of 
> the copper infrastructure.  So, people were able to get high 
> data rates on cheap circuits now and then if they were willing 
> to take a risk.  This doesn't happen anymore.

I don't know what they called them, but about 15 years ago by
now the local school district got point to point pairs to run T1
lines on for short distances. For all schools that were near enough
to the school central office, that was easy enough. They might
have chained through schools for farther away ones.

This was an upgrade from ISDN that they had earlier.  I don't know
what they do by now.

-- glen