Question

Loopback test how to

Asked by: steviedeehook

Hi,
How do I create a loopback cable for my ISDN card? and
How do I run loopback tests?

This Question has been solved and asker verified All Experts Exchange premium technology solutions are available to subscription members.

Subscribe now for full access to Experts Exchange and get

Instant Access to this Solution

  • Plus...
  • 30 Day FREE access, no risk, no obligation
  • Collaborate with the world's top tech experts
  • Unlimited access to our exclusive solution database
  • Never be left without tech help again

Subscribe Now

Asked On
2008-07-23 at 04:01:14ID23587984
Tags

Digium

,

ISDN PRI card

,

Wildcard TE12xP

,

Asterisk

Topics

Telecommunications

,

IP Telephony

,

Asterisk Open Source Telephony

Participating Experts
1
Points
250
Comments
14

Trusted by hundreds of thousands everyday for fast, accurate and reliable tech support.

  • "The time we save is the biggest benefit of Experts Exchange to Warner Bros. What could take multiple guys 2 hours or more each to find is accessed in around 15 minutes on Experts Exchange." Mike Kapnisakis, Warner Bros.
  • "Our team likes having a resource that is more secure than just using Google and most experts using this service really know their stuff. It's nice to look here first versus using Google." Dayna Sellner, Lockheed Martin
  • "Anytime that I've been stumped with a problem, 9 out of 10 times Experts Exchange has either the accepted solution or an open discussion of the potential solution to the problem." Kenny Red, eBay Inc.

See what Experts Exchange can do for you.

Got a question?

We've got the answer.

Experts Exchange has been collecting answers to technology questions since 1996…3 million and counting! If you have a question, chances are we already have your answer.

Screenshot of Experts Exchange Knowledgebase

Need individual assistance?

Our experts are ready to help.

If you can't find the exact answer you're looking for, ask our exclusive community of 50,000 experts. You’ll get a personalized answer from a trusted professional.

Screenshot of Experts Exchange Knowledgebase

Want to learn from the best?

Read articles from industry experts.

Thousands of free tech tips, tricks, how-to’s and tutorials are available in our peer reviewed articles section. See for yourself how smart our experts are, no login required.

Screenshot of an Article

Working on a long term project?

Store your work and research.

Save solutions to your questions, answers you’ve discovered through searching plus helpful articles in your personal knowledgebase for easy future access.

Screenshot of Experts Exchange Knowledgebase

Access the answers to your technology questions today.

Subscribe Now

30-day free trial. Register in 60 seconds.

What Makes Experts Exchange Unique?

Members of the expert community talk about why the experience at Experts Exchange is different than what you will find anywhere else.

Trusted by the world's most respected brands.

image of each brand's logo

Faithfully serving IT professionals since 1996.

Experts Exchange Logo

Try it out and discover for yourself.

Subscribe Now

30-day free trial. Register in 60 seconds.

Related Solutions

  1. What is a loopback cable ?
    after i assign IP address(Ex: 192.168.0.1) to my pc, I can't ping using the ip that i have assigned unless i connect my computer to a hub. I heard that we can make a loopback cable using UTP and we just connect one end of that cable to the pc and no need hub and then we can ...
  2. Loopback address?
    Got 2 stupid questions.. Looking at my web history within my firewall I noticed pages of http://127.0.0.1/heartbeat. When I went to Google it said, "Page can't be displayed." I checked out ARIN, they came back with a loopback address. I had to look that up a...
  3. loopback and ethernet
    1- I want to know if I ping loopback or 127.0.0.1 in a computer that doesn't have a network adapter, am I gonna have a reply? 2- what is the difference between loopback and ethernet thanks
  4. Ethernet loopback with port blinker
    I have been scouring the web for some plans to make an ethernet (rj45) loopback plug or jack that will make the link light on the device blink. I know there are cable testing tools for this, and I know I can do it with my t40 using the intel proset tools with the ethernet c...

Free Tech Articles

  1. WARNING: 5 Reasons why you should NEVER fix a computer for free.
    It is in our nature to love the puzzle. We are obsessed. The lot of us. We love puzzles. We love the challenge. We thrive on finding the answer. We hate disarray. It bothers us deep in our soul. W...
  2. SCCM OSD Basic troubleshooting
    SCCM 2007 OSD is a fantastic way to deploy operating systems, however, like most things SCCM issues can sometimes be difficult to resolve due to the sheer volume of logs to sift through and the dispe...
  3. Migrate Small Business Server 2003 to Exchange 2010 and Windows 2008 R2
    This guide is intended to provide step by step instructions on how to migrate from Small Business Server 2003 to Windows 2008 R2 with Exchange 2010. For this migration to work you will need the fo...
  4. Create a Win7 Gadget
    This article shows you how to create a simple "Gadget" -- a sort of mini-application supported by Windows 7 and Vista. Gadgets can be dropped anywhere on the desktop to provide instant information, ...
  5. Outlook continually prompting for username and password
    There have been a lot of questions recently regarding Outlook prompting for a username and password whilst using Exchange 2007. There are a few reasons why this would happen and I will try to cover t...
  6. Backup Exchange 2010 Information Store using Windows Backup
    There seems to be quite a lot of confusion around the ability to backup Exchange 2010 using the built in Windows Backup feature. This stems from the omission of this feature prior to Exchange 2007 s...

Cloud Class Webinars

  1. Avoiding Bugs in Microsoft Access
    Alison Balter takes and in-depth look at avoiding bugs in Access. In this webinar you will learn about using the immediate window to debug your applications, invoking the debugger, using breakpoints to troubleshoot, stepping through code, setting the next statement to execute, ...
  2. Top 10 Best New Features in Visio 2010
    Scott Helmers gives live demonstrations of the top 10 new features in Visio 2010. This webinar will teach you how to create compelling diagrams by adding shapes to the page with a single click, linking the shapes in a diagram to data in Excel (or SQL Server, or SharePoint), ...
  3. IT Consultant Business Secrets Revealed
    Michael Munger, Experts Exchange tech pro and IT consultant, pulls back the curtain on his very successful businesses and answers question on every IT consultant and business owner should know about. He shares secrets on what he did to solve the 5 most common problems in IT, ...
  4. Disaster Recovery and Business Continuity
    Quest CTO, Mike Billon, gives an overview of the steps involved in building a dunamic disaster recovery plan. Through case studies and an examination of software/hardware tooles for monitoring and testing, you'll gain a better understandin of where you are, where you want ...
  5. Organize Your Visio Diagrams with Containers and Lists
    Scott Helmers uses cross functional flowcharts, wireframe diagrams, data graphic legends and seating charts to teach you: how to ustilize all three new structured diagram components in Visio 2010, the best practices for organizeing shapes in previous version of Visio, how to organize ...
  6. How to Us Objects, Properties, Events and Methods in Microsoft Access
    Alison Dalter gives an in-depbth look at objects, properties, events and methods in Microsoft Access. In this webinar you will learn about using the object browser, referring to objects, working with properties and methods, working with object variables, understanding the ...

Join the Community

Give a Little. Get a Lot.

Join the community of experts here and help other tech pros by answering question in your area of expertise. You can earn FREE access to all Experts Exchange's premium features and resources.

Join the Community

Answers

 

by: grbladesPosted on 2008-07-23 at 04:18:48ID: 22067885

I got this from digium for a problem I was having a while ago.


/********
First you will need to make a loopback plug, you can make a loopback plug by taking a rj45
jack and running a wire from pin 1 to pin 4 and a wire from pin 2 to pin 5.
/********
If the card lights up green we will proceed with a quick edit of you zatpel.conf:

span = 1,0,0,ccs,hdb3,crc4
clear = 1-31
/********
Then run ztcfg -vv to configure the channels.
/********
Now you can build and run the tests.

cd /usr/src/zaptel
make tests

./patlooptest /dev/zap/1 60
Going for it...
/********
If nothing happes then you card should be fine
If it spews a bunch of errors, then something is wrong
/*******

 

by: steviedeehookPosted on 2008-07-23 at 07:33:23ID: 22069692

Thanks! :)
Can't wait to try it out.
Steven

 

by: steviedeehookPosted on 2008-07-23 at 10:17:32ID: 22071523

Hi,
When I pluggged in the loopback device I made the light on the card just stayed red....
Steven

 

by: grbladesPosted on 2008-07-23 at 11:00:06ID: 22072005

You might need to make the changes to the zaptel configuration and reconfigure the card depending on what the existing configuration was.
Give that a go first otherwise I would contact digium directly as they might have some more diagnostic tests you can run since there is a new major version of zaptel since I received these inctructions and you have a newer model card then I have aswell.

 

by: steviedeehookPosted on 2008-07-23 at 12:48:17ID: 22073096

I will try contact digium.
I was surprised that the line synced fine after un-plugging and re-plugging it - I could see that each of the b-channels was restarting 1 at a time. Is there a way to do an "indepth" restart like this from console / CLI? or did that come from Telco side? - it looks the same as when I ask them to reload their equipment.
Thanks
Steven

 

by: grbladesPosted on 2008-07-23 at 13:30:20ID: 22073517

I dont know of a way of doing it from the console. Perhaps stopping asterisk and reloading zaptel might do it.

 

by: steviedeehookPosted on 2008-07-24 at 08:36:02ID: 22080323

Fron Digium:

The patlooptest can be used to test ports on any of Digium's T1/E1 digital interface cards. This test transmits a bit pattern and listens for the same bit pattern to be received, comparing the results. To run the test, plug a T1/E1 loopback cable into the port to be tested.

After installing the RJ45 connector zttool should report green on the span.Use zttool to confirm that the span is "OK" (green alarm):
  zttool

If it is not green the T1/E1 loopback cable was made incorrectly.

Then configure the span as follows.

For a T1, /etc/zaptel.conf should contain:
  span = 1,0,0,esf,b8zs
  clear = 1-24

For an E1, /etc/zaptel.conf should contain:
  span = 1,0,0,ccs,hdb3,crc4
  clear = 1-31

Then, to configure the channels, run:
   ztcfg -vv

Now, make the tests, including patlooptest:
  cd /usr/src/zaptel
  make tests

Run the patlooptest:
  ./patlooptest /dev/zap/1 60
  Going for it...

The first parameter to patlooptest is the channel on which to run the test (e.g., /dev/zap/1 ). The test should be run on the first channel of the span in question.

The second parameter is an optional timeout (e.g., 60).

The test should complete with no errors. If there are errors, it may indicate that the card or port is bad. However, errors could also be caused by IRQMisses or a faulty loopback plug.

If patlooptest does not terminate after the timeout, the card is probably not taking any interrupts.

How do I know if I am T1 or E1?
The card specs say :

powerful interface supporting voice and data transmission over T1, E1, and
Primary Rate ISDN (PRI) connections

I've always known it as PRI. How do I find out if I'm T1 or E1?

Steven

 

by: steviedeehookPosted on 2008-07-24 at 08:43:22ID: 22080397

Hi,
I checked and triple checked my loopback connector.
1 - 4 and 2 - 5.
I used a cable tester, and asked someone else to check it again for me incase I was missing something stuid.... I'm sure it's right.

I plug it in and the light flashes red.

I stopped Asterisk and re-started zapte - still flashing red.

Steven

 

by: grbladesPosted on 2008-07-24 at 09:52:53ID: 22081178

T1 has 24 lines and is most common in the USA while E1 has 30 lines and is mainly a european standard. On the card I have there is a jumper on the card itself to switch between T1 and E1.

You could post a photo of the connector if you would like me to check it.

 

by: steviedeehookPosted on 2008-07-24 at 10:57:38ID: 22081772

we have 30 b-channels and 1 D channel - so I guess E1....
I have 2 photos of the card. Unfortunately neither of them include the jumper.
The light doesn't go green with the loopback in tho. and zttool is empty.
Steven

 

by: grbladesPosted on 2008-07-24 at 11:17:44ID: 22081950

Yes if you have 30 B channels it will be E1.
The connector looks correct and is how I have mine wired up.

I would double check the pins are connected together properly using a meter or perhaps just try making a new one. If you are certain the connector iis correct then I would contact Digium as it sounds like you have a faulty card.

 

by: steviedeehookPosted on 2008-07-24 at 11:37:49ID: 22082154

Hmm...
It works fine most of the time. :)
lol. I will make a new one just incase.
I have tested it with a cable tester ... is showed 1, 2, 4 and 5
Steven

 

by: steviedeehookPosted on 2008-08-06 at 04:18:45ID: 22168920

Still awaiting Digium's respnse.
Steven

20120131-EE-VQP-002

3 Ways to Join

30-Day Free Trial

The Experts

98% positive feedback on 31,087 answers since March 2000. angeliii is a Microsoft Most Valuable Professional for his work with MS SQL Server & Develoment.

He has also proven his knowledge of Visual Basic Programming, PHP Scripting and Oracle Databases.

The Experts

97% positive feedback on 10,752 answers since July 2000. lrmoore has more than 18 years experience in the networking industry.

The six-time Mircosoft MVPs specialties include firewalls, virtual private networking, and network management.

Testimonials

"...and excellent source for support... Kind of like having your very own IT dept." Electriciansnet

Testimonials

"I was apprehensive at signing up at first. However... it has already made my life as an IT administrator much easier." JaCrews

Testimonials

"WOW! You guys have great, active, and knowledgeable people on here." moore50

Business Clients

Business Clients

In the Press

"If you’ve got a question... Experts Exchange can supply an answer.”

In the Press

"...an invaluable aid for both IT professionals and those who require tech support."

In the Press

"where IT professionals provide quick answers on just about any topic"

Business Account Plans

Loading Advertisement...