[SATLUG] Re: New user requests advice.

MK Davis gtmo321 at earthlink.net
Thu Jul 9 15:27:24 CDT 2009

Is this your connection:    ( a)   ___telco wall 
|DSL Modem|--------------------------------computer (no filter)

 ( b.) or this:____telco wall jack------|dsl modem|----------Computer
| filter|--------------telephone?

If the "AC" is heard on you telephone(s), did you unplug you house 
wiring at the telco customer interface jack?  Was there AC noise still 
on your telephones?

Did you take a POT (plain old telephone) with a filter and plug into the 
teleco interface jack? AC noise?

AC or hum as I call it, is the results of a partial, short on the wire 
from the phone company.  The proximate  location of the phone interface 
to the house electrical service is seldom a problem.  The interface, I 
believe,  is locate near the electrical service to take advantage of the 
house common electrical ground.  No AC (hum) on your house interior 
wiring when you disconnect the teleco interface jack should eliminate 
that possibility.

The DSL modem may not appear to have a problem,the are suppose to  
operate at frequencies out of the audio range, and is able to buffer 
(store) and correct data. DSL system, in my opinion, is slow to begin 
with - so an additional reduction in speed may not be noticed.

If you recently had new interior wiring done for your dsl modem, I've 
found that cable staple gun to be a source of hum (ac) noise,

Other comments on this subject are on the money - this is just my take 
on you situation.   The question of whether polarity is important is 
iffy -  for a  POT,  it may not be a big deal.  For  a DSL  modem, 
caller ID (another data modem) and a telephone system with lots of bells 
and whistles...who knows.  If you want to correct your installation - I 
would suggest that you start at the customer interface.  This link may 
be of interest:



cdv7 at sbcglobal.net wrote:
> MK Davis wrote:
>> Dumb question: what do you mean by "AC" on computer line?  Is it the 
>> AC power outlet?  The telephone line?
>> Please and thank you
>> Mike
> Greetings Mr. Davis,
> The telephone line is referred to. Both my telephone and computer are 
> plugged into the same jack via the 2 Wire DSL filter.
> Concerning your question:
> It is wise to request a clarification; both parties are benefited and 
> it enables the person with an answer to give a  more accurate response.
> ~ cdv

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