Справочник Пользователя для 3com SuperStack II

This section describes the bridge/router response to a local loopback 
assertion and how to perform a loopback diagnostic test on the WAN 
and serial ports. It also describes the steps required to perform additional 
types of loopback tests for a T1/FT1 module.

If the bridge/router is connected to a DTE that asserts a local loopback 
signal, the bridge/router displays:

Path x Detected DTE Loopback ON, switching to echo mode

The bridge/router in echo mode transmits the received data back to 
the DTE.

When the signal is removed, the bridge/router displays:

Path x Detected DTE Loopback OFF, switching to normal mode

This section describes how to perform a loopback test on the built-in 
ISDN port on model 43x, 53x , 44x, and 54x bridge/routers.

Figure 9 shows the data flow that occurs when this loopback test is 
performed. Both B channels occupy the same physical connector and no 
TA is required in this configuration.

Figure 9   ISDN Loopback Testing

Before beginning this procedure, complete the following tasks:

■

Attach a console or Telnet to your SuperStack II bridge/router.

■

Configure the ISDN port according to “Configuring ISDN on the WAN 
Port (43x, 44x, 53x, and 54x)” on page 70.

B1 (Path 3.1)

B2 (Path 3.2)

Both channels (B1 and B2)
occupy the same physical connector

Port 3

Port 4