Digital Fax and DSL

[jerryreeve]

I got a flag that says to not connect DSL onto a digital fax line since it will knock out the DF. Anybody able to give me a run down on how "Digital fax" works and why the DSL filter would kill it? from my memory a voice bandwidth is nominal 4KHZ but the DSL operates in the GHZ range and only on the copper itself, it cannot go through drops that have a fiber component in them.

JerryReeve
Communications Systems Int'l
com-sys.com

 

[naturl]

Lets see, we can work this out...two technologies here, Digital and Analog. Digital Fax- Ethernet network; DSL- analog voice converted to Ethernet. One has to do with maybe a fax server and email on Ethernet. The other, voice line and higher voltages (+90V) You ever touch a voice pair when it rings? I should say it would knock out a DF (+5V) or at least make enough noise to render it ineffective. I can't say if the DSL filters out ring voltage-no-I say it doesn't, no ground sink. So passing analog voltage down a network line-bad idea. It's not the filter, it's the technology. We never share telephone and Ethernet on the same cable. True, fiber won't pass voltage. DSL is not a fiber technology-it is converted to Ethernet at the DSL modem-then whatever, on to the DF. Why did you get to wonder about this? The flag I can see; the various DF services out there I can't fully explain. Guys?

Why is there never a phone in the phone closet?