Specifications

2-39
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
Idle Code Suppression on the UVM
Idle code suppression (ICS) allows bandwidth savings on an nx64 super-rate data connection used to
carry video traffic conforming to the H.221 video codec frame protocol. The video channel is considered
idle at any time when identical data occurs in relevant time slots for 256 consecutive T1, E1, or J1
frames. Depending on the data channel size, the number of consecutive identical bytes necessary to
trigger idle code suppression can range from 256 to 2048 consecutive identical bytes.
To enable ICS on a data channel, use the switch software cnfdch command.
Tip In order to configure ICS on a data channel, the data channel must be used in an nx64 super-rate data
connection that terminates on either a UVM or a CVM.
Fax Relay on the UVM
The fax relay feature compresses the DS0 bit stream of a G3 fax connection to 9.6 kbps for transport
through the IGX network. Fax relay on the UVM is supported for LDCELP and G.729 connections.
Note Fax relay on the UVM is not supported for connections using the G.729A standard (or PCM or ADPCM).
After being enabled, fax relay overrides the automatic fax upgrade feature. However, a data modem will
still upgrade to PCM or ADPCM. This automatic upgrade feature suspends compression when a modem
or fax tone appears on a voice connection.
To configure a fax relay channel, use the switch software cnfchfax command.
UVM Front Card
A UVM front card can occupy any available front service card slot (slots 3 to 32). The module’s back
card depends on the desired line interface type. See the following usage information:
• For T1 lines, use the BC-UVI-2T1EC.
• For E1 lines, use the BC-UVI-2E1EC.
• For J1 lines, use the BC-UVI-2J1EC.
See Figure 2-17 for a description of the UVM front card faceplate.