While I'm not an expert on it, I think that the frequencies used by DSL currently are about the same as they always were. It's possible that they leave a little more 'buffer room' between the DSL frequencies and the lower phone ones. While people would complain about the DSL noise, I thought that the filters were even more for getting a good quality signal at the higher frequencies. You really don't want crappy low-cost phone equipment sending high frequency spikes through the lines and killing the DSL signal, which has a relatively low signal to noise ratio, especially as the loop length approaches the limits. The low quality jacks would allow a fair amount of cross-talk between the lines and wash out the signal, I assume. (But that's absolutely just a guess.)
If I was doing that work (which actually, on my house I will do within the next few months or year) if possible I would take the phone line directly to a DSL filter, and then take the DSL side of it directly to the modem, and the other side wired to the rest of the house. That way as little as possible of the wiring would have the higher frequencies, which would provide for a cleaner signal, and likely a little higher maximum broadband rate. What you saw makes sense to me. Erik On Thu, Mar 21, 2019 at 11:46 AM Michael Barnes <[email protected]> wrote: > Not really Linux related, but you're the best group I know to ask this. > > I haven't dealt with DSL for some time. One person I help out recently went > back to Century Link DSL from satellite. When I dealt with DSL years ago, > the phone line ran to the modem, then from the modem to other phones in the > house. If you went to a phone that didn't go through the modem, you needed > a filter. In this installation, the existing house wiring consisted of odd > collections of non-telephone wire, including thermostat wire, doorbell > wire, and other unidentified stuff. Although it worked, the bandwidth was > atrocious with speeds barely at dial-up service. There were no filters in > the system, but I did not hear the expected "DSL buzz" on the other phones. > I installed a new run of CAT6 cable, using one pair for the line from the > Century Link interface box to the modem. Surprisingly, the modem would not > lock on to the DSL. I had used a cheap RJ-11 jack labeled CAT3, which > turned out to be the problem. When I replaced the jack with a CAT6, > everything locked in and we had 3+ mbps of service. > > So, my questions are, first, does today's DSL use a higher frequency signal > that no longer needs filters to prevent it from being heard in other phones > on the line? Also, if that is the case, would some cheap Chinese CAT3 jacks > somehow block or distort the DSL signal, preventing the modem from > detecting it? Through exhaustive DC continuity testing, I determined > everything was wired correctly and polarity was proper. The analog phone > signal worked just fine. It was all very perplexing. > > Thanks for any insights to this. > > Michael > _______________________________________________ > PLUG mailing list > [email protected] > http://lists.pdxlinux.org/mailman/listinfo/plug > _______________________________________________ PLUG mailing list [email protected] http://lists.pdxlinux.org/mailman/listinfo/plug
