[cisco-voip] Echo on PSTN calls

[Brian Lehigh]

Thank did the trick.  Thank you, Jonathan.

-Brian

On Sep 4, 2008, at 8:36 AM, Jonathan Charles wrote:

> Um, no, it should be external (unless it is a PTP, then you set one  
> side to external, and the other to internal).
>
> You need to do a network-clock-select t1 1 [interface of PRI]
>
> Set it to first preference and the slips will go away... and set it  
> to line clocking.
>
>
>
> Jonathan
>
> On Thu, Sep 4, 2008 at 10:15 AM, Brian Lehigh <brianl at sti.net> wrote:
> Jonathan,
> Thank you for the reply.  Sure enough I have a bunch of slips on  
> both T1's.  Clock was set to external on both so I'll try changing  
> that first.
>
>
> -Brian
>
> On Sep 3, 2008, at 5:06 PM, Jonathan Charles wrote:
>
>> Echo is a function of the analog 2-wire to 4-wire conversion in the  
>> hybrid transformer at the central office.
>>
>> IOW, it doesn't happen on PRIs.
>>
>> In all likelihood, the echo is actually coming from the other side...
>>
>> However, check your T1 for slips, since you already have the echo  
>> cancellers are maxed out...
>>
>> You can also try this:
>>
>> voice-card 1
>>  codec complexity medium ecan-extended
>>
>> However, I don't think you can do that with a PRI already  
>> configured...
>>
>> What are the input gain and output attenuation?
>>
>>
>>
>> Jonathan
>>
>> On Wed, Sep 3, 2008 at 4:07 PM, Brian Lehigh <brianl at sti.net> wrote:
>> Hello all,
>> We have a 2811 with a VWIC2-2MFT-T1/E1 running MGCP with two PRI to  
>> the PSTN.  The 2811 is running 12.4(13r)T. We're running Call  
>> Manager 6.1.2.
>> Some end users are complaining of echo when placing calls to the  
>> PSTN.  All users have either 7941 or 7961 phones.  SW Echo  
>> cancellation is enabled on both PRI with a 64ms Echo Cancellation  
>> Coverage.  We have tweaked QoS, etc. and just can't seem to reduce  
>> it.
>> Is there anything else we can do to suppress some of this echo,  
>> short of buying the hardware expansion module?
>>
>> Thanks,
>>
>> -Brian
>> _______________________________________________
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>> cisco-voip at puck.nether.net
>> https://puck.nether.net/mailman/listinfo/cisco-voip
>>
>
>

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