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T1-CAS and MGCP. Hookflash problem


Hello - I have CCM 4.2(3) and a 3845 MGCP gateway. Between the gateway and my legacy IVR (Edify Workforce) I have a T1-CAS circuit. I can successfully place a call into my IVR. My IVR has a script that allows me to input an extension and be transferred. When I punch in the extension on my IP phone, the IVR sends a hookflash to my 3845 gateway over the T1-CAS. When this happens I get disconnected. I tried to set up hookflash on CCM with T1-CAS but it seems that the only option for signalling is E&M. I'm curious why that is??? My IVR needs to do loop-start. I know this is the reason things aren't working right. Any suggestions on how to solve my hookflash problem would be appreciated.



18 Replies 18


Change your gw to H323.

CCM supports E&M winks start and delay dial only in MGCP mode

It doesn't work with H323 either.


Did you ever get a response to this? I am having the same issue you described.

Has anyone had any luck with this...I am trying to do the same thing...



It should work - T1 CAS Hookflash feature is now supported in IOS (MGCP). Previously it used to be supported only on 6608.

You need to run CCM 4.2 and IOS IOS 12.4(6)T or later. You configure a 'timing hookflash-in ' command on the voice port.

Please refer the following URL for (brief) CCM documentation:

It looks like this feature may have been missed in CCM version 5.0, but will be in version 6.0.

This looks good; but i have the same issue as a previous poster with it not working in H.323 either. Do you know if this IOS resolves that as well?

Thank you so much in advance!

There is a TCL application that you can download that allows call transfer via hookflash on H323 gateways-

file is ''

I have not heard of anyone using it for T1 , but it should work. If you need to customise the script, you may need a developer support service contract to get assistance from the TCL application developers.

We have dowloaded the script and are in the process of getting it to work with in our enviroment. I beleive it will be a solution for our needs...I also noticed you mentioned something about modifing the script...we will need to do this..does anyone know a good resource for information on the tcl programing...Is there a forum we could post our questions...



Did this work for you? I have tried every flavor of this script that i can come up with with no success.

Yes we have got this working with h450 transfer script...we still have some issues we are trying to resolve...we are trying to get some help with the scripting from our SE...let me know what issues you are having and maybe I can help you out...


Hi Joe,

Do you have to run CM 4.2 and CAS T1 configured as E&M?




we are running into the exact issues as the user who posted this question. Wer have CM 4.1.3 and a 3845 voice gateway. The 3845 is connected to an Intervoice IVR server. Everthing works fine except when a user tries to zero out to an extension, they get dropped. Our IVR system tries to do a hookflash transfer. We are connected to them via fxs loop-start ports that we configured from a single T1. It is all H323. So you're saying that with the tcl it can work?

I would appreciate your help.

Vince Doan

Nexus IS


We did this with E&M, but I imagine you may have a similar issues that we did.

There is a hookflash timer that resides on the voice port in MGCP. I tried everything I could do, but I can get it to change from the default whioh is 450ms or something like that.

So we had someone change the hookflash timer on the Edify side to match the router. Then it all worked.

Not applicable

Hey do u know what the vendor changed there hookflash timer to..I am having the same problem with a siemens and a cisco.

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