DSL experts...can single pair support fax+dsl modem?

[spidey07]

Just as post says.

I'm trying to help a buddy out and don't know much about residental class DSL.

His requirements:
(1) POTS line for phone calls anytime.
(2) Separate FAX line able to accept calls anytime.
(3) Always ON dsl connection so he can't get his A$$ fragged by me on a daily basis.

I thought RES wiring was two pair twisted. I thought you can run one pair as your POTs ine and another pair as your DSL/FAX line. The DSL/FAX line can be an always connected internet connection and still receive/send FAX no matter what. Am I mistaken or do you need three pair in to accomplish these requirements to a tee? I'm in bell south(err...hell south) territory BTW.

DAMAGED.....where you at? I know some boys at the CO who can hook me up with updated switching gear but generally need to know if this is even in the realm of possibility without going to business class DSL. I'm thinking ISDN functionality here.

 

[spidey07]

bump...cause I'm an impatient SOB.

 

[Xanathar]

DSL(not HDSL) can share pairs with any voice communication. Since Modems and Faxes use the same frequencies as voice that WILL work. Have fun You do need a provider that supports it thou (different head end equipment) most Independent Clecs cant (like covad) but the ones that use Bell's (east coast at least, SBC, USWest are the same way) are configured to share dsl and a phone line.

 

[JackMDS]

You can not fax from the computer with a DSL modem, but other Fax machines, and Telephone equipment can share the line.

You have to install a special filter on each one of the other instruments. (These filters usually come with the modem).

 

[spidey07]

ahh, i see. So the passive filters mute the higher freqencies used by DSL passing only the 56k analog to the fax line?

Let me get this straight. I need one pair/line for POTs service/phone. The other pair I can use as both an always on connection DSL and a residential fax machine? the fax machine can take calls no matter what the dsl is doing? Of course this is all dependant on the switching equipment at the other end.

I hope this is correct, cause me and my girlfriend are going to pull some strings for my pal with the LEC (aka bells) for this kind of service. I believe the bells here consider this a "business" class of service and hence charge appropriately for it.

'preciate it fellas!!!

 

[Eug]

POTS (incl. fax, voice, and modem), HomePNA networking, and aDSL all use separate frequency ranges so that they can all be used simultaneously on the same physical copper wire pair. I know, since I've done it.

By the way, my "separate" fax line is actually my same phone line. My fax has a different phone number which rings differently so that my fax can pick it up before my answering machine does.

Anyone know if things like phones and faxes need the filter when they're NOT in use? I'm wondering since I currently haven't bothered filtering my fax, phone, or my home security system.

 

[Mday]

hmmm

when not in use...

i actually did this.

without the filter, when the phone has a signal (incoming call or off the hook) the dsl "link" dies. that is, the signal is pretty much dead. and my connection goes.

but that was a few weeks ago when i was having phone problems due to the actual cable being screwed up outside.

 

[AKA]

If your gonna have 2 phone lines, why not just have 1 line for fax only. And the dsl line for always on and phone calls, since being online wont affect your incoming or outgoing calls.

 

[spidey07]

AKA

The scenairo you just described was how I thought DSL could work. A single pair incoming to a resident could be used as both a DSL connection and a phone number/line without interferring with each other?????

According to EUG this is perfectly acceptable. If so then my buddie's dilema is solved, I just have to convince the local bell that it is so. I also heard that this capability is strictly dependant on if your copper runs directly into a central switching office (CO). If my buddy gets muxed up on fiber somewhere then he is SOL?

Thanks again for your help fellas. I'm trying to convince our incumbant LEC that this is indeed possible, even though level one customer serivice is giving my friend the run around (amazing what you get for $6/hour). FYI - I do have access to the CO if I need to bypass the fiber mux.

cheers!

<edit> grammar and spelling...looks like another bacardi and coke for me. No beer shadow

 

[shadow]

I believe the major thing for DSL wiring that you have to worry about is that you pass over no more than (and hopefully none at all) load coils on the way to the CO. I don't think fiber has anything to do with it. <edit>I should learn to keep my mouth shut...<edit>

 

[shadow]

<< <edit> grammar and spelling...looks like another bacardi and coke for me. No beer shadow >>

huh? you got the right thread here spidey? maybe that's one bacardi and coke too many......

 

[DSLer]

If there is any fiber in your buddy's loop, he is hosed. It may also be referred to as &quot;pair gain&quot;, or &quot;digital loop circuit&quot;. These two uses of fiber actually enable the Telco to push multiple phone numbers (different customers) over a single pair, and then split it at a neighborhood box. These two situations also tend to affect whole neighborhoods, so it does no good to ask the Telco to switch you to another pair.
Load coils are another story. Their intented use is to strip off high-frequency noise, enabling a basic signal to run farther down the cable pair, and are used mainly for long (18,000 ft +) loops. The Telco may offer to remove them for you.
Another problem is &quot;bridge taps&quot;. This is unterminated cable somewhere past your address, where the cable pair used to go to an address farther out. Since it usually doesn't affect regular phone service, it wasn't removed, in case you move, and they need the cable farther out. It does reflect an ADSL signal back, and can cause problems, and loss of signal. It is possible to remove this too, sometimes, but it is up to the Telco to remove it or not. Until recently, if someone in my area had a loop longer than 12,000 ft, the Telco charged $900 to remove bridge taps and load coils up to the 17,500 ft limit of service, but still wouldn't guarantee the removal would provide DSL service.

 

[spidey07]

Thanks a bunch DLSer

Lots of good info