[cisco-voip] Echo on IP Phones through PRI

[Matthew Melbourne]

Thanks Steve. We have an upgrade planned for our voice gateways in an
forthcoming maintenance window, where we'll try 12.4(latest) mainline.
Are you aware of any bugs which document this issue?

Cheers,

Matt

On 09/05/07, Steve G <smgustafson at gmail.com> wrote:
> 12.3(14) will deffinietly give you echo issues.  it is the DSP firmware.
> either get new DSP firmware from TAC, or upgrade IOS.  I am using 12.4(8)b
> with no issues.
>
> Steve
>
>
> On 4/18/07, Matthew Melbourne <matt at melbourne.org.uk> wrote:
> >
> > We are getting sporadic issues from users on IP phones who are hearing
> > echo on external calls. From this document is would suggest that echo
> > on IP Phones is caused by hybrid echo and not any local acoustic echo.
> >
> >
> http://www.cisco.com/warp/public/788/voice-qos/echo_ipphone_gateway.html
> >
> > The MGCP-controlled voice gateways are all running 12.3(14)T7 with DSP
> > firmware 4.4.708. In CallManager (4.1(3)SR2), echo cancellation is on
> > for each port, with a "default" echo cancellation coverage of 64ms.
> > Input gain and output attenuation are set to 0dB.
> >
> > I have seen suggestions to include the "echo-cancel erl worst-case 3"
> > command on the voice ports. Can this help in situations of occasional
> > echo?
> >
> > Are there any other parameters changes which could help? Could it be a
> > code/DSP firmware issue? I haven't found a specific echo-related bug
> > relating to this particular IOS and its embedded DSP firmware.
> >
> > On occasions, the start of the call is fine but echo comes and goes
> > during the call.
> >
> > Is there a quick way of finding out which voice gateway a call is
> > terminated on (we have 8, and all could be used in a round-robin
> > fashion for outbound calls).
> >
> > Cheers,
> >
> > Matt
> >
> > --
> > Matthew Melbourne
> > _______________________________________________
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> > cisco-voip at puck.nether.net
> > https://puck.nether.net/mailman/listinfo/cisco-voip
> >
>
>


-- 
Matthew Melbourne