SBM powered by Microsoft Lync™ Administrator's Guide 2011-11

6-7

Troubleshooting

Implement a Loopback

When your PSTN connection has an LOS alarm, but you cannot determine the

error, you might put the line into a local loopback to determine the problem.

In addition, your PSTN carrier might ask you to put the circuit in a loopback

mode for testing.

There are two general types of loopback:

 Local—The SBM sends data to the CO, which loops it back to the SBM.

In this case, you are responsible for initiating the BERT and analyzing the

results.

See “Implement a Local Loopback” on page 6-9.

 Remote—The PSTN carrier controls the testing. The CO sends data to

the SBM, which loops the data back through the interface to the CO. The

CO can then initiate Bit Error Rate Tests (BERTs), which are bit patterns

that are designed to detect problems.

See “Implement a Remote Loopback” on page 6-18.

Implement a Local Loopback

Complete each section to place your SBM in local loopback.

Ensure the Gateway is Not Running

First shut down the Media Gateway:

1. Access the SBM Dashboard. (See “Access the Dashboard” on page 3-3 of

Chapter 3: “Manage and Monitor the HP SBM Locally” if you do not know

how.)

2. In the Services section, click the Stop button next to HP Media Gateway.

If you prefer, you can alternatively open a command line (remember to right-

click and select Run as Administrator) and enter this command:

net stop netborder express gateway

Determine the Interface ID

See “Determine the Interface ID” on page 6-3 if you need help.