If this loopback test fails, there's a problem with the serial connection between the sites.At the remote site, perform a loopback test from your Telnet connection to the problem device.At the NOC, unplug the serial cable from the remote site and loop the cable's TX pin to the RX pin with a paper clip or screwdriver. If the remote site port is OK, next test the connection between the remote site and the NOC.If the loopback test fails, the port may be defective. If the loopback test is successful, the port is physically OK.Without the loopback, you should not see the character echoed. Now remove the paper clip from the port and type a character. You should see the character echoed on the screen. Perform a loopback test: Type any character.Make a Telnet or proxy connection to the problem device.At the remote site, unplug the serial cable to the NOC and loop the port's TX pin to its RX pin with a paper clip or screwdriver. First, verify that the device at the remote site is OK.Note: you need two techs for this: one at the NOC and another at the remote site. Troubleshooting a problem serial connection between a remote site and the NOC is not too different from troubleshooting a local serial connection, as described in Section 4, "How to Test RS-232 Connections with a Screwdriver or Paper Clip."
0 kommentar(er)
