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Customizing CAS…

12 Aug

Ever been troubleshooting an issue to find the problem was you left out a single line of code – code you never knew needed to be there?  I’m betting anyone who’s been in IT for any length of time has been there, done that- and nearly pulled his/her hair out in the process. (Why do you think there are so many balding guys in IT?)

Case in point – team lead and I are bringing up E1 circuit in Mexico, resting comfortably in the knowledge that we’ve done this before. The fact that we have no idea how many digits the carrier is going to be sending doesn’t even phase us, we’ve got mad translating skills – bring it on.

That is until it’s clear that whatever digits the carrier is sending, the router is less than thrilled with. No modification of the incoming translation pattern appeases the angry stream of incoming digits- whatever they may be.

Fast forward about two hours and quite a number of debugs later and say hi to the Australian TAC engineer, who is now on the line with us, two IT guys at the site, and a Mexican telco engineer.  Only problem – no one but the telco engineer speaks Spanish – and we’re pretty sure everything that’s wrong is his fault.  He is the telco guy after all.

In the bizarre world of coincidences, the Australian TAC guy (with the really great accent, btw) pipes up with  “hey, the guy in the cube next to me happens to speak Spanish” – and with that our international summit gains traction.  Shortly after, we are staring in awe at the magic line of code that makes everything in this particularly odd universe super happy.

What was missing? This line: groupa-callerid-end. Yep, all this madness and mayhem over that one single line.  It goes here:

controller E1 0/0/0
framing NO-CRC4
ds0-group 1 timeslots 1-15,17-30 type r2-digital r2-compelled ani
cas-custom 1
country telmex
category 2
answer-signal group-b 1
groupa-callerid-end  

Now will you always need this command when bringing up E1s?  Nope.  Will this fix all your issues with telcos in Mexico?  Not likely.  But it’s definitely something to make note of.  Especially when you find yourself doing a bit of guesswork due to a certain lack of information and relatively huge language gap with the carrier.

As an added bonus and completely unrelated to the issue above – here are some dial-peers for common patterns in Mexico that might prove useful if you are planning on bringing up a site there.  Think of it as your treat for making it to the end of this post.

dial-peer voice 2 pots
description Local Dialing
destination-pattern 9[1-9]…….
port 0/1/0:1
forward-digits 8
!
dial-peer voice 91 pots
description Long distance
destination-pattern 901……….
port 0/1/0:1
forward-digits 12
!
dial-peer voice 9011 pots
description International Dialing
destination-pattern 900T
port 0/1/0:1
prefix 00
!
dial-peer voice 44 pots
description Local Cell Phone
destination-pattern 9044……….$
port 0/1/0:1
forward-digits 13
!
dial-peer voice 45 pots
description Long Distance Cell Phone
destination-pattern 9045……….$
port 0/1/0:1
forward-digits 13
!
dial-peer voice 60 pots
description Emergency Services
destination-pattern 060
port 0/1/0:1
forward-digits all
!
dial-peer voice 9060 pots
description Emergency Services
destination-pattern 906.$
port 0/1/0:1
forward-digits 3

dial-peer voice 9070 pots
description Information & Electric Repairs
destination-pattern 907[01]
port 0/1/0:1
forward-digits 3
!
dial-peer voice 9050 pots
description Telephone Repair
destination-pattern 9050
port 0/1/0:1
forward-digits 3
!
dial-peer voice 9040 pots
description Information
destination-pattern 9040$
port 0/1/0:1
forward-digits 3

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20 Comments

Posted by on 2011/08/12 in CAS, E1

 

20 responses to “Customizing CAS…

  1. Rob Gartley (@rgartley)

    2011/08/12 at 07:57

    Nice post and yes… we’ve all been there! I have to keep this one in my back pocket when we bring our Mexico site on IPT.

    groupa-callerid-end – Countries like China, Thailand, and Mexico use Group-C signals for ANI collection. If this is configured, the router uses the Backward Group-A-1 signal as Caller ID End. If it is not configured, the router uses the country default, which might be a Group-C signal.

     
    • amyengineer

      2011/08/12 at 08:12

      That’s good to know! I’ll be filing away that information as well!! Thanks!

       
    • Angel Castaneda

      2011/08/12 at 08:16

      @Amy
      Great post. Saving this one, just in case 🙂

      @Rob
      Good to know! I was about to ask why this statement was needed.

       
  2. Ted Trentler

    2011/08/12 at 08:31

    Nice tool for my toolbox

     
  3. Ethan Banks

    2011/08/12 at 18:10

    “Only problem – no one but the telco engineer speaks Spanish – and we’re pretty sure everything that’s wrong is his fault. He is the telco guy after all.” Bwahahahahahahaaaaaa…just awesome. Keep writing. I don’t do voice at all, and you’re writing my new favorite blog.

     
    • amyengineer

      2011/08/14 at 18:50

      Wow, thanks for the encouragement, I may be blushing a bit now! I really do appreciate hearing the positive feedback, especially from experienced bloggers like yourself!! 🙂

       
  4. daveengineer

    2011/08/26 at 21:30

    and i read this as I am trying to bring up an e1 r2 in telmex land now.. sadly this command wasnt the magic command..

     
    • amyengineer

      2011/08/28 at 16:22

      Sorry to hear! I was bringing up a T1 CAS on Friday night and couldn’t find a magically command for that one either…bleh… 🙂

       
  5. daveengineer

    2011/08/29 at 16:17

    Turns out it wasnt a telmex circuit… it was alestra.. so this is the final config that made it work.

    controller E1 0/1/0
    framing NO-CRC4
    line-termination 75-ohm
    ds0-group 0 timeslots 1-15,17-31 type r2-digital r2-compelled ani
    cas-custom 0
    country telmex use-defaults
    category 2
    answer-signal group-b 1

     
    • amyengineer

      2011/08/29 at 19:52

      Awesome – I’ll be filing this one away, I’ve never seen the line-termination command used…

       
  6. Jerry Hubbard

    2011/09/04 at 15:35

    Amy I agree with Ethan Banks your blog is awesome.

    I’ve only worked on digital PBX phone systems. This is the deep end of the pool. I follow the concepts and some of the configuration info. Please keep writing.

     
    • amyengineer

      2011/09/12 at 10:15

      I don’t believe I ever said thanks for the positive review! Very much appreciated!!

       
  7. Fracamm

    2012/01/29 at 15:31

    Lot of thanks Amy. This post saved our migration today !

     
  8. Fernando Atilano

    2012/05/29 at 11:51

    Hi, Im currently having a Caller Id Issue with one of our customers, the controller configuration is as follows:

    controller E1 0/0
    framing NO-CRC4
    ds0-group 1 timeslots 6-15,17-31 type r2-digital r2-compelled
    ds0-group 2 timeslots 1-5 type r2-digital r2-compelled
    cas-custom 1
    country telmex use-defaults
    category 2
    answer-signal group-b 1

    I added the groupa-callerid-end with no change on the caller id issue.

    His PBX is a Meridian Option 61, any feedback will be greatly appreciated,

    ps GREAT BLOG !

     
  9. gm3gm

    2017/10/14 at 15:11

    Hi Guys,

    I am trying to bring Alestra PRI UP in Mexico. I have applied the below configs but still showing down. Actually, controller is showing down, Framing, Line code are confirmed correct with Alestra. Our onsite engineer confirmed crossover cable is connected between Cisco VG and Alestra side. What else could be the problem ? In the meanwhile, i have requested Alestra to confirm the below config is what we need to use on user side. For E1 ISDN, we use debug isdn q921 to check whether SAMBE message are getting exchanged . What debugs to use for R2 ? . Any help will be appreciated. Thanks !

    framing crc4
    line-termination 75-ohm
    ds0-group 0 timeslots 1-15,17-31 type r2-digital r2-compelled ani
    cas-custom 0
    country telmex
    category 2
    answer-signal group-b 1
    groupa-callerid-end

    E1 0/1/0 is down.
    Applique type is Channelized E1 – unbalanced
    Transmitter is sending remote alarm.
    Receiver has loss of signal.
    alarm-trigger is not set
    Framing is crc4, Line Code is HDB3, Clock Source is Line Primary.
    International Bit: 1, National Bits: 11111
    Data in current interval (452 seconds elapsed):
    0 Line Code Violations, 0 Path Code Violations
    0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins
    0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 452 Unavail Secs
    Total Data (last 6 15 minute intervals):
    0 Line Code Violations, 0 Path Code Violations,
    0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,
    0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 5400 Unavail Secs

     
    • amyengineer

      2017/11/10 at 09:24

      Sorry, I missed this comment! We’re you all able to solve this issue? What was the fix? I haven’t encountered this exact issue, was it a physical issue? I’ve encounter situations where a standard crossover cable was used instead of a T1 crossover. What debugs did you end up using? I think I relied a lot on debug voice ccapi inout when dealing with CAS, but it has been awhile…

       

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