Specifications

T1 CSU/DSU

2.4 Loopback Switches

There are two Loopbacks switches on the front panel of the of the T1 CSU/DSU. Both switches allow the

user to test individual sections of data transmission path. This ability to test these individual paths allows

the user to isolate, diagnose, and then perform corrective action to resolve data transmission problems

in the network.

2.4.1 R

EMOTE CSU/AGGREGATE LOOPBACK

The REMOTE CSU/AGGREGATE LOOPBACK (see Figure 2-1) test lets you verify the logic from the

local interface through the remote aggregate and back to the local channel interface. To select this test,

position the AGGREGATE LOOPBACK switch in the REMOTE position. When complete, return this

switch to the center position.

Figure 2-1. Remote CSU/Aggregate Loopback.

2.4.2 R

EMOTE CHANNEL LOOPBACK

To verify the remote unit’s channel logic from the local unit (Figure 2-2), select the remote position of

the AGGREGATE LOOPBACK switch. When complete, reposition this switch to the center position.

Figure 2-2. Remote Channel Loopback.

2.4.3 L

OCAL CHANNEL LOOPBACK DIAGNOSTIC

Local Channel Loopback Diagnostic (Figure 2-3) enables you to verify the channel interface. To run this

test, position the CHANNEL LOOPBACK SWITCH in the LOCAL position. When complete, reposition

the switch to the center position.

Figure 2-3. Local Channel Loopback.

Test

Equip.

CHANNEL CHANNEL

Test

Equip.

CHANNEL CHANNEL

Test

Equip.

CHANNEL CHANNEL