Subject: RE: (usr-tc) CT1 problem / Line Coding Errors

From: Richard Gamberg <[email-masked]>
Date: Sat, 12 Feb 2000 08:50:56 +0000

[My earlier attempt to post regarding this subject didn't make it due to using different smtp server]

-> -----Original Message-----
-> From: [email-masked]
-> [mailto:[email-masked]]On Behalf Of Mark Thornton
-> Sent: Friday, February 04, 2000 12:19 PM

-> I am having a problem on three incoming CT1's that are 
-> terminated by the T1
-> card to quad modems. We are seeing "bipolar violations", "code violation
-> errors", and "bursty errored seconds". The telco has looked into the hdsl
-> carrier and it shows no errors. Neither does the central switch. 

> I began looking for problems when the number of people 
-> complaining about not
-> being able to stay online jumped significantly today. They report the
-> problem has been going on for the past two days.
-> 
-> Does anyone have any thoughts on what these errors point to? 

Line coding errors?
Check out the new updates to my "Line Coding Errors" page at
http://808hi.com/56k/coding.htm

Line coding errors may be much bigger issue than some think - can also occur in telco/clec facilities between subscriber and your switch - something you have little control over!

CT1 = beginning of recipe for 56k trouble
get PRI if at all possible.

Aloha,
Richard
http://808hi.com/ 56k=v.Unreliable

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From: Terry Kennedy <[email-masked]>
Date: Sun, 13 Feb 2000 01:21:45 +0000

Is this really true? That CT1's are more prone to problems
than PRI?

Aloha,
Richard

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From: Charles Sprickman <[email-masked]>
Date: Sun, 13 Feb 2000 02:47:42 +0000

> Is this really true? That CT1's are more prone to problems

What was very confusing about the statement (and not true) is there was an
implication that CT1s performed worse when there were line coding
mismatches somewhere in the chain.

Being the victim of said problem, I can tell you it is equally nasty no
matter what the delivery method...

Charles

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From: Ronald Kushner <[email-masked]>
Date: Sun, 13 Feb 2000 03:26:36 +0000

> matter what the delivery method...

Yeah, if you have problems with line coding between the Tandem and the end
office, or in the DIOTs, it doesn't matter if you have ISDN Prime, CH-DS1,
you're going to have problems. 

The best thing is to keep on the telco to make sure all their trunks are
configured properly. ISDN won't work when it hits a mismatched DS-1s in a
trunk group. It is true that you will sometimes get about 2400bps on average
better connect speed when you use PRI over CH-DS1.

-Ron
GLISnet, Inc.
+1 810/939.9885

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From: Aaron Nabil <[email-masked]>
Date: Sun, 13 Feb 2000 05:04:33 +0000

> Is this really true? That CT1's are more prone to problems

No, of course not.

The paper also make some other rather misleading statements, like
"STANDARD TESTING WILL NOT DETECT LINE CODING MIS-MATCH".  Which is
abusrd, line coding problems are one of the many things tested for 
when a T1 is turned up.  The point, if any, is that automated testing may
not detect line coding problems.

> http://808hi.com/ 56k=v.Unreliable

Aaron Nabil

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