Opening a fract T1 for modem access in Linux

[Gerald Combs]

On Fri, 13 Sep 2002, Duane Attaway wrote:

> On Fri, 13 Sep 2002, Jared wrote:
> 
> > I really appreciate your information, and will start looking for a
> > digital modem instead of a regular analog. Is there a site I can
> > go to for more of this kinda information?
> 
> Here is a nice description of how T1 hardware really works if you are 
> interested.  It may help understanding how it works to be able to look 
> past the marketing behind the products:
> 
> http://www.shout.net/~wildixon/telecom/t1/t1.html

Great link!  I think that he should have spelled out the fact that a DS0
is the line that Bell runs to your house, a.k.a. a POTS (plain old
telephone system) line.  He also didn't explicitly state that a T1 and DS1
are the same thing.

BTW, the page up one level at http://www.shout.net/~wildixon/index.html
has lots of useful info as well.

> Being able to troubleshoot your own equipment can determine if it is your
> problem or the telephone company.  When they do not wish to look into the
> problem, sometimes troubleshooting skills become necessary.  I was able to
> connect a scope on my isdn line once and determine the phone company had
> some serious noise comming into my house.  Even though they didn't
> understand what an oscilloscope was, my ISP did.  And the heated calls
> from my ISP to the telephone company got a telephone guy out to my house
> at 4am Sunday morning.

When I worked at an ISP, they were kind enough to pay for an ISDN line at
my house.  A few weeks after it was installed, it stopped working.  The
tech came out, tested it and declared it good.  The problem was that he
only tested it for voice connectivity - the switch at SBC was rejecting
data connections (ISDN makes a distinction between the two).  It took
several days of pestering to get them to admit to a problem and fix it.

I've found that SBC more often than not impedes troubleshooting instead of
facilitating it.  Knowing how the gear and plumbing works lets you cut
through the line of bull they often feed you.