On dialup, the farm couldn't negotiate modem speeds quite as fast as I
> could in town. I assumed the limitation was in the wire. That's why
> I was amazed to see that DSL seems to use the wire in the same way as
> dialup. Was I wrong to think the reason dialup data rates were slower
> at the farm was that the wire to the CO is longer?
The length of the wire DOES play a part. Also, how the wire is buried or cabled, along with it being 'concentrated' by multiplex equipment en route to the central office. This is why the farm would be slower than in town.
What's the downside for the telco? With the right pricing, I think
> they could tap a huge market for increased bandwidth.
There is no downside for the telco and there is a huge market for increased bandwidth.
The speed of DSL will vary though depending on physical set up of the wire pair between the home and central office, as mentioned. What is perfectly fine for voice may cause interference in high speed data transmission and force the speed to be lower. The physical arrange- ment of the wire, known as the "loop plant" varies tremendously. Some of it is old. Some of it is bundled in cables in such a way that works for voice but not so good for data due to tiny bits of interference -- just enough to cause a bit drop out in high speed communication. Other cables go through multiplexors that may limit throughput.