3Com S330 manual Setting VCM Port Loopbacks, Setting VCM Channel Loopbacks

Using Loopbacks 183

Setting VCM Loopbacks For the Voice Compression module, you can set both card/line and channel loopbacks. When you set a VCM loopback, the MCPU sends a message to the VCM card to perform a maintenance function, and the VCM replies with an acknowledgment. When the VCM enters maintenance mode, it generates an alarm to the MCPU. Only one maintenance function per port or per channel is allowed.

Setting VCM Port Loopbacks

To set VCM port (card/line) loopbacks, follow these steps:

1From the Loopback Menu, shown earlier in Figure 136, enter the number corresponding to the slot number in which the Voice Compression module is installed (7 or 8) to open the VCM Loopback menu. Figure 143 shows the VCM T1-DSX menu. The VCM E1 menu is the same.

Figure 143 VCM Loopback Menu

2Select [1] Set Port Loopback to open the VCM Card/Line Loopback menu. This menu is similar to the OC3/STM-1 Loopback menu, shown earlier in Figure 139.

3Select the option corresponding to the type of loopback you want to perform, and set the loopback to On.

Local Card—Loops the transmit VCM output on the receive side; the transmitted data will continue to go on the output.

Network Line—Loops the VCM received data back on the output side after the digital data has been recovered.

Network Card—Loops the T1-DSX received payload back toward the line output.

Setting VCM Channel Loopbacks

To set VCM channel loopbacks, follow these steps:

1From the Loopback Menu, shown earlier in Figure 136, enter the number corresponding to the slot number in which the Voice Compression module is installed (7 or 8) to open the VCM Loopback menu.

2From the VCM Loopback menu, shown in Figure 143, select [2] Set Channel Loopback.