Hello Leo, Thank you very much for this information. I saw a similar post to my current issue but I wanted to see if I can please get some feedback on mine since it is a bit different? Current issue is with a few VOIP Cisco phone devices. The Corporate Directory sometimes is not functional and the only way to resolve this is by a hard power cycle of the devices. All devices (about 7) are located in the same building, different switches. All device logs indicate a possible issue with the network.  I am getting a lot of TCP-timeouts, KeepaliveTO, etc errors for all the devices been effected. However, users are not reporting that the devices are rebooting or loosing power....The reason that I think the users are not reporting the devices loosing power is because the devices are going into fail-over mode. But anyways, just wanted to give you a little background information.    I decided to run some TDR cable testing on each device after reviewing the device logs.    These two are on the same switch:  Switch Ports Model SW Version SW Image ------ ----- ----- ---------- ---------- * 1 52 WS-C2960S-48FPS-L 12.2(55)SE8 C2960S-UNIVERSALK9-M   Interface Speed Local pair Pair length Remote pair Pair status --------- ----- ---------- ------------------ ----------- -------------------- Gi1/0/29 100M Pair A 27 +/- 0 meters N/A Normal Pair B 25 +/- 0 meters N/A Normal Pair C 27 +/- 1 meters N/A Short/Crosstalk Pair D 27 +/- 1 meters N/A Short/Crosstalk   Interface Speed Local pair Pair length Remote pair Pair status --------- ----- ---------- ------------------ ----------- -------------------- Gi1/0/21 100M Pair A 24 +/- 0 meters N/A Normal Pair B 24 +/- 0 meters N/A Normal Pair C 25 +/- 1 meters N/A Short/Crosstalk Pair D 25 +/- 1 meters N/A Short/Crosstalk   This devices in on a different switch, different floor, same building: Switch Ports Model SW Version SW Image ------ ----- ----- ---------- ---------- * 1 52 WS-C2960S-48FPS-L 12.2(55)SE8 C2960S-UNIVERSALK9-M   Interface Speed Local pair Pair length Remote pair Pair status --------- ----- ---------- ------------------ ----------- -------------------- Gi1/0/36 100M Pair A 47 +/- 0 meters N/A Normal Pair B 47 +/- 0 meters N/A Normal Pair C 47 +/- 1 meters N/A Short/Crosstalk Pair D 47 +/- 1 meters N/A Short/Crosstalk   What I am having issues understand is why does the Remote Pair report "N/A" for all interfaces? Also, just based on the results from Pair C and D for all interfaces is it pretty safe to assuming there is a problem with cabling? I can't find anything explain what "Crosstalk" indicates. It sounds pretty straight forward on what it is but would still like to know the Cisco definition for it. Thank you very much.  ... View more