VWIC2-1MFT-T1/E1 for ISDN data backup?

Unanswered Question
Mar 9th, 2009


I have Cisco 3845 with VWIC2-1MFT-T1/E1 card. I would use this card for ISDN backup (data traffic).

When I put pri-group timeslots 1-31 on interface controller e1 0/1/0 I got an error:

% Not enough DSP resources available to configure pri-group on controller E1 0/1/0

% The remaining dsp resources are enough for 0 time slots.

% For current codec complexity, 2 extra dsp(s) are required to create this voice port.

So, is it possible to configure ISDN data backup with this card and how?

On the branch office I have WIC-1B-S/T V3.



I have this problem too.
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vjemin Mon, 03/09/2009 - 06:54

Hi Giuseppe,

I will use this card for ISDN DATA backup, so I don't see that I need DSP resources.

I'll have ISDN signalization on link.

One solution is with HWIC-1CE1T1-PRI card, but my customer have this card.

Am I right?


Giuseppe Larosa Tue, 03/10/2009 - 01:13

Hello Vlaho,

>> I'll have ISDN signalization on link.

this is the point and that VWIC misses the HW to perform that on its own, so it is dependent on the network module it is inserted in.

You need to add some piece of hardware to the router to achieve ISDN PRI functionality

Hope to help


vjemin Tue, 03/10/2009 - 16:04

Hi Giuseppe,

it seems that you are right.

One solution is to use HWIC-2CE1T1-PRI card, or take PVDM and software 12.4(4th)T and do some more configuration.

So, with these MFT card a data traffic is terminated on HDLC controllers and voice and video traffic is terminated on DSPs.

For configuring pri-group timeslots on controller I should have DSP's on platform. Then I got serial interface for voice calls only, but with a new software we can configure that serial interface is for data traffic.

All that configuration and hardware because of ISDN PRI functionality and data traffic.

So, be careful when they say that MFT cards support data traffic.



cg100668 Mon, 05/17/2010 - 22:10


Did you manage to use the VWIC2-1FT-T1/E1 card for ISDN data back up?  I am in the same situation. Could you please give me the details how to proceed with the configuration? Please post your configuration.



vjemin Tue, 05/18/2010 - 01:08


I put some other piece of hardware for ISDN backup .

I have used HWIC-1CE1T1-PRI and the older NM-1CE1T1-PRI.

This is configuration on the central site for PRI interface:

interface Serial0/3/0:15

no ip address

encapsulation ppp
dialer rotary-group 1
dialer-group 10
isdn switch-type primary-net5
no peer default ip address
fair-queue 64 256 0
no cdp enable
ppp authentication chap
interface Dialer1
ip address
encapsulation ppp
no ip split-horizon eigrp 1
ip summary-address eigrp 1 200
dialer in-band
dialer-group 10
no peer default ip address
fair-queue 64 256 0
no cdp enable
ppp authentication chap
ppp multilink


access-list 110 permit ip any any
dialer-list 10 protocol ip list 110

Kind regards,


cg100668 Tue, 05/18/2010 - 01:16


Thanks for the mail. However as I said, the customer has got VWIC2-1MFT-T1/E1 and he does not want to purchase the HWIC card. For other customers we have already use the HWIC card.



vjemin Tue, 05/18/2010 - 01:22

I know your problem. I have a good customer .

Maybe you can try with refurbished parts?



Paolo Bevilacqua Tue, 05/18/2010 - 12:00

With routers (and other stuff), only thing that matters is what the product does, not what a customer wants.


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