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transconding

Hi,

I have a analog phone conected to a fxs port in the 2821 router(using sccp). If this analog phone call to a ip phone (local or remote), is transconding resources requiered ?.

1 ACCEPTED SOLUTION

Accepted Solutions

Re: transconding

Hi Rafael,

The FXS port is going to use DSPs no matter what, since it is an analog connection. Since these are the same DSPs that do transcoding, it's fairly equivalent to transcoding.

Depending on what codec CUCM negotiates with the gateway, the DSP will simply change what codec it is using.

This isn't something to worry about, unless your DSP resources weren't allocated correctly for high complexity codecs.

You can use the DSP calculator to be sure:

http://www.cisco.com/cgi-bin/Support/DSP/cisco_prodsel.pl')">http://www.cisco.com/cgi-bin/Support/DSP/cisco_prodsel.pl

hth,

nick

3 REPLIES
Hall of Fame Super Silver

Re: transconding

No it is not as the GW can negotiate any codec.

Chris

Cisco Employee

Re: transconding

what codec have you configured each device to talk?????

if G711 there is no need

HTH

java

if this helps, please rate

HTH

java

if this helps, please rate

www.cisco.com/go/pdi

Re: transconding

Hi Rafael,

The FXS port is going to use DSPs no matter what, since it is an analog connection. Since these are the same DSPs that do transcoding, it's fairly equivalent to transcoding.

Depending on what codec CUCM negotiates with the gateway, the DSP will simply change what codec it is using.

This isn't something to worry about, unless your DSP resources weren't allocated correctly for high complexity codecs.

You can use the DSP calculator to be sure:

http://www.cisco.com/cgi-bin/Support/DSP/cisco_prodsel.pl')">http://www.cisco.com/cgi-bin/Support/DSP/cisco_prodsel.pl

hth,

nick

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