ext_100281 ([identity profile] erikvolson.livejournal.com) wrote in [personal profile] timill 2007-03-24 04:30 pm (UTC)

Rule of thumb, if you have a decent DSL modem. Wait 5 days, it'll constantly be trying various channel and skew settings. Sometimes, this results in the line dropping.

Think of an eye test. "Is this better or worse?" (click) "worse." "Okay" (click click) "Is this better or worse?"

My personal experience. Day one, slow, day two fast, day three flakey, day four, drops, day five slow, day six and beyond, fast.

Now I'm going to speak BellSpeak. The other thing to do is to install a splitter at the demarc point, put a good filter on one line, and use that to support your terminal equipment. The other part of the split go straight to the DSL adapters, thus, the line only has one split point, and one filter reflecting signals back ontop of the DSL signals.

The problem with the filters-at-terminal is you end up with multiple reflections at the very end of the line. If one of the extensions is just the right length, it'll slaughter the incoming signal, and the DSL adapter and DSLAM have to change the signal to try to accommodate such. Another is you're increasing the inductive load on the far side of the filter, this makes the filter work better -- better to load five phones on the far side of one filter than one phone behind one filter five times. This only applies with modern phones, if you have the UK equivalent of the old (bulletproof) Western Electric phones (You know, large, ABS, copper bells, that sort,) they'll present more than enough inductance to make the filter operate in almost an ideal fashion. A friend keeps one plugged in just for that reason -- he unplugs it, and his bandwidth slowly drops by 300kbps over a day, then he plugs it back in and it climbs again. Another reason is the larger demarc filters are better built than the microfilters for terminal equipment -- High quality inductors and capacitors take up physical space.

This probably won't translate. If you do get a service call, ask them to "cut dead ahead" of your demarc. Translation -- after terminating your pair, cut the line so that any cable further along is isolated from your phone. This also reduces reflections. The reason they'd leave the cable is that if you move, it makes it easier to move your circuit elsewhere. This was rather important in the days before houses had multiple pairs running to every premise, nowadays, the only time they'll move a circuit is to replace a damaged one, and if they do that, they're often pulling new copper anyway.

Hopefully that translates into English. I don't know how UK phonesets are wired -- I took one look at a UK electrical panel and went "I clearly do not understand this. Call a professional." Someone then explained ringmains, and I said "I clearly do not understand the English. Call the barkeep." But the influence of Bell Telephone was mighty, and while power jacks are a crapshoot, phone systems seem to be much more uniform and universal -- the plugs are sometimes weird, but the signals on the wire pair are very similar. P




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