User`s guide

Section 360−381−C02

4.12 Loopback Test (DSU/OCU − Primary T1 Only)

Use the Loopback test to check where on the line problems are occurring when an alarm is reported on the card.

See the DSU documentation and the OCU documentation for additional information on loopbacks.

Loopback Test OCU/DSU Menu

Select Card

CSU Loopback

Direction

Apply New Settings

Select Channel

OCU Loopback

DSU Loopback

Local LPBK

2047 Pattern

Enable

Near

Disable

Use the following steps to enable/disable the card loopback.

Step Action System Response

1. Select which card you want to test (Card 1, Card 2

or half size)

Displays your choice

2. Select the channel number to test.

Use the <Tab> key to highlight the channel num-

ber and <Enter> to select the channel

Flags the channel

3. OCU Loopback. Select latching or unlatching

(unlatching is not available at the 64K rate)

Displays selection

4. CSU Loopback. Select latching or unlatching

(unlatching is not available at the 64K rate)

Displays selection

5. DSU Loopback. Select latching or unlatching

(unlatching is not available at the 64K rate)

Displays selection

6. Local LPBK. Select enable or disable Displays selection

7. Direction. Select near or far Displays selection

8. 2047 Pattern. Select enable or disable Displays selection

9. Select Apply New Settings to save your choices

and enable/disable the loopback

If you have chosen to enable the loopback, this will

start the test. You will have to go back into this

menu and select Disable to end the test.

Note: DSU/OCU, near and far end loopback generators, do not function when the ICB is equipped with a sec-

ondary T1 card operating in the T1 protect mode.