### Conducting a Loopback Test

Use this procedure to perform a loopback test to ensure that a port on a Digi One RealPort or PortServer TS 2/4 device server is working properly.

#### Before You Begin

The IP address should already be assigned to the device server and the serial port must be configured with the set ports command as a printer.

If the test is successful, the terminal will display the characters you enter from a telnet session. If the port is not working properly, you will not see data displayed. Further troubleshooting will be necessary.

#### Procedure

To conduct a loopback test, do the following:

1. Plug the power cord into the Digi One RealPort or PortServer TS 2/4 device server.
2. Plug the RJ-45 loopback plug into the serial port to be tested.
3. From the DOS prompt, telnet to the IP address of the Digi device server.
   An example is: telnet 143.191.2.151
4. Login as root with the default password dbps.
5. Enter connect 1 (one) to connect to the first serial port. (If you are testing the 2nd serial port, enter connect 2, etc.) The following message appears:
   Set escape character to ^[
6. From the cursor, begin entering characters.
   If the port is working properly, the characters will be displayed on your PC monitor.
7. Repeat this test if you have other ports to test.