DSL Filters ?

Dick Rucker rrucker at bellatlantic.net
Tue May 6 21:34:09 CDT 2003

on 5/6/03 16:28, Andre Kesteloot at andre.kesteloot at verizon.net wrote:

> Gang,
> DSL Line conditioners, or filters, are installed between the incoming
> telephone line and each telephone set. The blurb states that "the
> in-line DSL filter eliminates all erratic impedance from telephone
> equipment that interfere with DSL".
> See for instance:
> http://www.suttleonline.com/pdfs/900SeriesAdapters.pdf
> Does anyone actually know what this is supposed to mean?
> 73
> André

DSL uses the bandwidth of the twisted pair above 25 kHz, while the
telephones in your house use that below 25 kHz.  The low pass filter is
placed in parallel across the incoming line to provide a voice-only path for
your telephones.  Your DSL modem is connected to the unfiltered incoming

"Erratic impedance" isolation may be a by-product of that low-pass
filtering, though I'd not heard of that aspect before.

Dick, KM4ML

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