Specifications

Chapter 1 Product Overview
Application Notes
1-12
Catalyst 4224 Access Gateway Switch Software Configuration Guide
OL-2031-02
The DSPs compress and decompress packets based on codecs. The Catalyst 4224
supports the following codecs:
• G.711 a-law 64 Kbps
• G.711 mu-law 64 Kbps
• G.729 abr 8 Annex-A & B 8 Kbps
• G.729 ar8 G729 Annex-A 8 Kbps
• G 729 r8 G729 8 Kbps
The number of DSP channels that you can use depends upon the VIC
configuration. The following rules apply when you allocate DSP channels for
T-1/E-1 VWICs:
• The eight-port FXS Module uses two of the six DSPs by default, leaving four
DSPs to configure for digital voice.
• The maximum number of T1/E1 DS0s that you can configure is 24 on the six
available DSPs. The eight-port FXS module must be disabled using the CLI;
otherwise, only 16 channels are supported by four available DSPs.
• Only use DSP channels if you configure voice DS0s.
• Each set of four DS0s uses one DSP.
• One entire DSP is used even if less than four DS0s are configured. Five DS0s
use two DSPs.
• T1/E-1 DS0 channels cannot be used for analog channels.
Note You can disable the eight-Port FXS Module using the command line interface
(CLI), and thereby free up eight DSP channels for additional digital voice
channels.
The following rules apply when you allocate DSP channels for BRI, FXS, and
FXO VICs:
• The two-Port BRI VIC uses two of the available four DS0 channels if you
configure voice. You can use the other two DS0s for voice FXS or FXO, but
not T-1/E-1.