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VG224 - Unknow Number

Trying to configure a Port on a VG224 (12.4-15(T5) on CCM 4.13(Sr7) for faxing - when dialing from the fax machine the caller ID shows “unknown number” you can fax from it but unable to receive faxes to it. I've reboot the CCM associated to this VG, shut and un-shut the voice port, moved to another port on the VG with same results. I can see the number hitting the voice gateway (3845) but doesn't ring the fax machine or when using a butt set on the line. I've seen this before on another VG224, rebooting the CCM fixed that one but not this one - any help is greatly appreciated.


Frequent Contributor

Re: VG224 - Unknow Number

The problem is with the fax traffic getting from your main gateway to the VG224, it is not an issue with traffic from the VG224 towards the main gateway. Most common reason this happens - clock slips on the PSTN gateway digital trunks. Assuming you have some kind of T1/E1 gateway, do a show controller and check the stats - if you see clock slips then this could be the problem. The reason why the faxes work VG224 ---> PSTN is the traffic in this direction does not experience slips, but the traffic PSTN ---> VG224 has slips in the bit stream, which cause errors in the data, the fax protocols detect these errors and retransmit, but the errors keep occurring and eventually the fax machine drops the call. Assuming you have a T1 card in slot 0/0/0 of the PSTN gateway router, you need the following commands -

network-clock-participate t1 wic 0

network-clock-select 1 t1 0/0/0

this will recover the clock signal off the PRI on controller e1 0/0/0 and use it to drive the DSP's and the traffic in the TX direction, so there will be a common clock reference system wide and the slips should be cleared.


Re: VG224 - Unknow Number

Thanks - I'm using a 3845 with FULL DSP resources, did the show controller and didn't have any slip indications, I found if I shut and unshut the port - eventually the number will be usable, not sure what causing it.


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