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New Member

ratio of DSP's to voice calls


Could someone point out good documentation on the relationship between DSP's and the voice channels or calls.

Please correct me of i am wrong, you require 1 DSP for 1 voice channel or voice call.


New Member

Re: ratio of DSP's to voice calls

you are correct.

New Member

Re: ratio of DSP's to voice calls

There are two kinds of Cisco DSP modules; the 542 and the 549. The 542 is the modules used in the devices that only support the FXO/FXS WICs. These support 1 FXx call per DSP and cannot, to the best of my knowledge, be used as a DSPFarm for conferencing or transcoding.

The 549 is the kind most often refered to when taking about DSPs. These are the DSPs used to support high-density voice in 2600/3600 and the 175X routers. These can be used to set up a DSPFarm for transcoding and conferencing, depending on router platform. The number of calls they support depends on the complexity of the codecs in use. One 549 DSP can support 4 Medium-complexity codec (i.e g.711) calls (apperently the PR people didn't like "low-complexity") and 2 high-complexity codec calls (i.e. g.729).

If you want to look it up yourself you can here:

and here: