3560 Switch Won't Recognize 7942G phone

[MICHAEL BURNS]

I am having an issue where I have a switch that won't recognize a new phone I am installing.  The port provides power, but it is in a down state.  Below is the debug ilpower events output when I plug in the phone:

719208: Aug  8 12:17:32.954 CDT: ILP uses AC Disconnect(Fa0/12): state= ILP_SHUT_OFF_S, event= CLI_START_DETECT_EV

719209: Aug  8 12:17:32.963 CDT: ILP uses AC Disconnect(Fa0/12): state= ILP_DETECTING_S, event= CLI_START_DETECT_EV

719210: Aug  8 12:17:33.466 CDT: ILP uses AC Disconnect(Fa0/12): state= ILP_DETECTING_S, event= IEEE_CLASS_DONE_EV

719211: Aug  8 12:17:33.466 CDT: %ILPOWER-7-DETECT: Interface Fa0/12: Power Device detected: IEEE PD

719212: Aug  8 12:17:33.541 CDT: ILP uses AC Disconnect(Fa0/12): state= ILP_IEEE_PD_DETECTED_S, event= IEEE_PWR_GOOD_EV

719213: Aug  8 12:17:34.959 CDT: %LINK-3-UPDOWN: Interface FastEthernet0/12, changed state to down

Any ideas??  It seems the the switch doesn't recognize it as a Cisco IP phone.

[paolo bevilacqua]

Check if pins are bent inside the phone socket. Or it can be a faulty phone.

[Leo Laohoo]

Looks like it's a faulty cable.

Do you have happen to have a 3560G/E/X or 3750G/E/X in nearby for you to test?  The appliance need not be PoE.

[MICHAEL BURNS]

I tried various cables, plus I have it plugged directly into the switch, so it can't be a bad drop. 

I forgot to mention that when I plug it into a 3750X stack that I have in a different IDF, it comes right up.  Seems to me that it is an issue with the switch, however, I also tried using a power brick with poe disabled on that port and I am still getting the "ethernet disconnected" message.  I can plug my laptop into the port with no issues.

[Leo Laohoo]

I forgot to mention that when I plug it into a 3750X stack that I have in a different IDF, it comes right up.  Seems to me that it is an issue with the switch, however, I also tried using a power brick with poe disabled on that port and I am still getting the "ethernet disconnected" message.  I can plug my laptop into the port with no issues.

Are you using the same cable when you plugged the phone directly to the 3750X?

I tried various cables, plus I have it plugged directly into the switch, so it can't be a bad drop.

Can you explain the physical cabling?  Do you mean something like this:

switch <--> patch cable <--> patch panel <--> horizontal cabling <-> patch panel <--> cable <--> phone

[MICHAEL BURNS]

Yes, I used the same cable that I used on the 3750X.

To avoid any cabling faults, it is plugged directly into the switch.

switch <--> patch cable <--> phone

I know this is a bit bizzare...

[Leo Laohoo]

Yes, I used the same cable that I used on the 3750X.

Coool!

Plug it back to the 3750X and run the following commands:

1.  Command:  test cable tdr interface ;

2.  Wait for approximately 5 to 7 seconds;

3.  Command:  sh cable tdr interface ; and

4.  Post the output to #3.

[MICHAEL BURNS]

Here you go:

BMR_1219_SW#sh cable-diagnostics tdr interface gi2/0/23
TDR test last run on: August 08 22:11:54

Interface Speed Local pair Pair length        Remote pair Pair status
---------     -----     ----------      ------------------ ----------- --------------------
Gi2/0/23  auto    Pair A     N/A                N/A         Not Completed
                        Pair B     N/A                N/A         Not Completed
                        Pair C     N/A                N/A         Not Completed
                        Pair D     N/A                N/A         Not Completed

[Leo Laohoo]

You got this result from a 3750X?

Wow.  That's a bad cable run if you have waited 7 seconds and you get "Not Completed" result.

So if you plug the phone directly to the 3750X using the same patch cable, it works, right?

[MICHAEL BURNS]

Phone is up and running on the 3750X.  Not sure why it is showing up at Not Completed. 

[Leo Laohoo · Accepted solution]

Not sure why it is showing up at Not Completed.

On a 3750X, "Not Completed" will come up if the cable tested is really, really bad.