ADSL: too far from the CO? Use a second pair?

If 2400 is the best they can do, they have the sync screwed-up - classic.

Don

I think you should have specified DPG (digital pair gain)... And if telco doesn't have it on the drawing board, then it doesn't matter how much one was to beg... it aint gonna happen.

You need what is called "Pair gain" to extend the distance. Make sure that not only are you sitting down, but have your seat belt on when you ask what it will cost.

Hell, The folks three miles further up the road from me are ALL on pair-gain equipment. Which, I'm told by the phone guys who have shown up at my place to fix problems, is the reason that they count themselves lucky to get a 2400 (yes - two, four, zero, zero) bps connection when they try to dial into an ISP.

Say if we need a thicker cable to transmit signals better, then one could just add additional strands no? And what if these strands just happened to come with insulation? Anyway, am I not just still increasing the surface area along which the signals flow? And what if these strands just happened to be two pairs out of a bundle of 100, etc.

But in comp.dcom.xdsl 31 Aug 2005 Re: too far from the CO? Use a second pair they tell me 9 women can't make a baby in 1 month etc. Sniff.

"Don Bruder" wrote in message news:TlqTe.12396$p% snipped-for-privacy@typhoon.sonic.net...

"Pair gain" may mean different things to different folks. For example audio gain amplifiers and/or inductive 'loading' coils, typically 88 millihenry added at distances of, IIRC, each 6000 feet to improve voice pair losses, on very long telephone loops. That treatment works up to an analog frequency of around 3500 hertz! Loading, while reducing the lower frequency loss, in particular, 'cuts off' higher frequencies due to the added inductance, limiting bandwidth. A company I worked for did various pair gain work when a local US military base closed down. It's USAF private branch exchange was taken out of service. Following that subscribers in the base area, wanting telephone service were connected on very, very long loops to the private telephone company serving the civilian community some distance away. To improve telephone voice transmission various audio gain devices were added; even so the loops had very high resistance, which could affect signalling/dialling, especially back in the old rotary dial days! We don't get much really hot weather here; but on one or two exceptional days the resistance of some copper wires, inside the overhead black jacketed cables increased to the extent that telephone dialling failed; just couldn't get dial tone. At night things cooled down and telephones worked again! However 'pair gain' can also mean adding devices such as a 'subscriber line carrier'; this is often a transistorized device which mounted at the telco main frame and out on pole or in someone's house etc.. uses low frequency 'carrier' signals over existing cable pairs which are already in use. This is done to avoid, say, installing any more cable on existing fully loaded pole structure or in already full underground conduits! In other words this 'gains (the equivalent of) more pairs'! I seem to recall that such devices could be installed quickly for about $125; heck of a lot cheaper and quicker than running, say 5 miles of cable. So, for example, YOUR main phone might be on a cable pair; but that pair may also be used via one of those devices to provide telephone service, just POTS (Plain Old Telephone Service) to Mrs Smith two doors down. Naturally while the telco has met its obligation to provide telephone service such methods mean very poor bandwidth, both on the pair itself and the added service. Conditions which tend to require the use of pair gain devices tend to be farthest out from telephone company switching exchanges or 'wire centres' and/or are 'pockets' of residential development! Our telco here will not provide DSL service beyond certain defined limits; they will however do a test if the area is considered marginal or the customer insists. Our DSL comes about one kilometre over the same pair as our standard home telephone. As mentioned if the telco has to special conditioning, amplifiers rearranging of pairs in order to get DSL to work, it can get expensive. I have acquaintances who live just too far out in the country, as it were, to get DSL for the foreseeable future.

Everyone who reads this should do so carefully. It lacks..... Well that sums it up.

it depends what the problem is.

probably not a bad thing

yeah, by addiing an extra pair you decrease the resistance (and thefore the thermal noise) but it may not reduce all noise effects,

The DSL equipemnt is tuned to the impedance of a standard copper pair, if you parallel a second pair the impedance changes and it stops working.

You'd need some sort of matching transformer at both ends or possibly need to redesign the outpuut circuitry of the DSL units, I don't know of any place you can get that sort of stuff off the shelf.

yeah it's a bit likee that.