Specifications

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Cisco IGX 8400 Series Provisioning Guide, Release 9.3.3 and Later Releases
OL-1166-04
Chapter 2 Cisco IGX 8400 Series Cards
Universal Voice Module
Tip To configure more than 16 channels for LDCELP or CSACELP with G.729, you must configure the
UVM to pass remaining time slots to a second UVM for processing through configuration of line
pass-through. During line pass-through, one UVM port connects to user equipment and the other port
connects to another UVM. For more information on line pass-through, see Chapter 7, “Cisco IGX 8400
Series Voice Service”
Voice frequency compression ratios can be determined through selection of a kbps rate for the voice
channel. For example, a 64 kbps voice channel does not compress voice traffic. A 32 kbps voice channel
compresses voice traffic at 2:1. See Table 2-24, “Cisco IGX 8400 Series Voice Service” (Chapter 7),
and the Cisco WAN Switching Command Reference for more information.
Voice g729ar8 24 (T1)
30 (E1 and Y1)
CSACELP Carries 8 kbps CSACELP voice in accordance with the
G.729A standard.
Voice g729ar8v 24 (T1)
30 (E1 and Y1)
CSACELP Carries 8 kbps CSACELP with VAC voice in
accordance with the G.729A standard.
Data t 24 (T1)
30 (E1 and Y1)
– Carries 64 kbps clear channel data.
Data td 24 (T1)
32 (E1 and Y1)
– Carries 64 kbps or lower compressed data.
Data nx56
nx64
16 – Super-rate data connections where n is less than or
equal to 8.
Note A super-rate connection is formed by
aggregating up to 8 contiguous clear channel
data channels. They are frequently used for
video.
1. All voice connections can be configured for fax or modem upgrades.
2. In order to support CSACELP, the UVM must run UVM firmware Model D or later. To determine the firmware model running on the UVM, use the
switch software dspcds command.
Table 2-23 Connections Supported by the UVM (continued)
Connection
Type
Switch
Software
Parameter
Maximum
Number of
Channels
Voice Coding
Type Description
Table 2-24 Voice Compression Ratios According to Channel Transmission Rates
Transmission Rate Voice Compression Ratio
64 kbps Voice traffic is not compressed
32 kbps 2:1
24 kbps 8:3 (~ 2.66:1)
16 kbps 4:1