[SATLUG] Re: New user requests advice.

Geoff geofff at w5omr.shacknet.nu
Thu Jul 9 17:58:41 CDT 2009

I've been trying to understand this...  My explanation might sound
simplistic, but bear with me... let's talk the same language and I
-think- we can get through this.

>> The telephone line is referred to. Both my telephone and computer are
>> plugged into the same jack via the 2 Wire DSL filter.

Computers require AC voltage from the electrical outlet (called an
electric jack in some circles) and telephones do -not- plug into
electrical jacks.

So, I'm gathering that when you say your 'telephone' is plugged into the
same jack as the the computer, you mean the telephone line out of the
computer, and the plain ol' telephone (POT) are plugged into the same
TELEPHONE jack.  This is not the correct way to connect an AT&T 2Wire
DSL modem/router.

The DSL modem/router plugs into a twin RJ-11 'pigtail' that has, on one
end, a regular telephone jack (RJ-11) and on the other end has two,
side-by-side RJ-11 female jacks.  The regular end of this 'pigtail'
plugs into an unfiltered telephone jack on the wall of your dwelling. 
On the other end, the side marked DSL/HPNA connects to your DSL modem. 
The other is marked "Phone" and that's where you plug in your POT (plain
ol' telephone).

Let's please be specific when addressing each jack, be it electrical or
telephone.  Telephone female receptacles are "phone jacks" and
Electrical AC Outlets are "AC plugs".

Now that we're clear on terminology, when you say "AC on the line",
let's try a few things to determine where it's coming from.  I lived in
an old, old house that had 1950's wiring.  It wasn't until the late 60's
and early 70's when electrical devices depended on AC polarity, so I've
been through this exact process before.

1) Unplug every line from every telephone jack in the house. 
Everything.  No phone, no where.

2) Go out to the junction box, unscrew the bolt and remove the jack that
powers the house.  This is the interface box between the Telephone
Company (telco) and your dwelling.

3) Grab up your POT (plain ol' telephon) and plug it into the jack you
just opened up, and check for dialtone.
at this point, you are liable to hear a lot of hash/trash on the line
and a carrier that sounds like it is looking for a connection.  This is
the DSL signal coming down the line, looking for the DSL modem.   If you
hear this noise, then grab up one of the regular in-line filters, and
plug -it- into the jack, then your POT into the filter. 
A Regular in-line filter has a single male plug for the telephone jack,
and a single female jack that your POT plugs into.

4)  Check again for dialtone.  If you get one, press a digit so the
dialtone goes away, and listen for 'hum' on the line.

*If you have hum, stop here* and call the telephone company.  It's
-their- problem.

If you don't have hum, then plug back in the jack that provides
telephone to the dwelling and go to each telephone jack on the walls in
the dwelling and plug your filtered POT into each, repeating step 4 at
each jack.

If you don't hear any hum on any of the jacks, then plug your filtered
POT into a jack (any jack), and then, one by one, plug your regular
telephone devices back into  their respective jacks. 


After each device is plugged in, check the POT for hum, again.  Check
after each device is plugged in, one by one.  Eventually, you'll find
the offending device. 
If all devices show no hum, then plug in the DSL modem again, and check
for hum.

Chances are, at this point, the DSL modem has a problem, -or- the
Electrical outlet is wired backwards.

I got lost when you said you were checking each line for AC, and
couldn't tell if you were checking the phone jacks or the electrical
outlets.  From reading the thread, I'm not the only one confused ;-)  Of
course, each electrical outlet is going to have AC on it.  It's supposed

Do the checks on the telephone jack at the user interface box first,
then check the inside of your dwelling.

Methodical and thorough checking will gain results.  Let us know what
you find.


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