Northern UTA220/UTA220k manual Port Tests, Local Terminal Loopback, Local Loopback Test

Diagnostics

PORT TESTS

Port communications tests are initiated and terminated via the front panel under the PORT TEST submenu of the DIAGNOSTIC OPTIONS. The following section describes each of the tests, when to use them and what it means if they fail.

Local Terminal Loopback

Local terminal (DTE) loopback loops data back to the DTE by connecting the TD and RD pins so that whatever the DTE sends is echoed back (Figure 14-2).

Figure 14-2. Local Terminal Loopback Test

To initiate the test, select LOCAL TERMINAL LOOPBK option from the PORT TEST submenu. The UTA220 may be on-line or off-line when the test is initiated. Any protocol, mode, and DTE rate can be used. The test is successful if the data is successfully echoed back to the DTE. A BERT device can be helpful in checking for data errors. This test verifies the operation of the DTE, the DTE cable, and the DTE interface of the UTA220.

Local Loopback Test

Local loopback loops data from the local terminal back to the terminal so that whatever the terminal sends is echoed back (Figure 14-3). Also the RTS pin is echoed on the CTS pin and the DTR pin is echoed on the DSR, DCD, and RI pins. Run this test if you are encountering data errors before and after data calls are placed. This test is useful in diagnosing the DTE and the UTA220.

14-2 UTA220/UTA220k