7941 Phones - Network Disconnects with new PCs Connected to PC Port

[Matthew Martin]

Hello All,

We've recently began swapping out our old Dell CallCenter PCs with new Lenovo m715q Thin Desktop PCs.

On a handful of these workstations, when the Desktop PC gets plugged into the Phone's PC port, the screen blanks (*except for wallpaper/background on phone) and the PC has no network access.

If I unplug the desktop PC from the back of the phone the 7941 immediately reconnect/re-registers back to cucm within seconds. Then, plugging the PC back into the PC port the same things happens again.

I read a few bug reports on similar issues. One pointing to Automatic Port Configuration, which I'm not exactly sure what is meant by that. Also, someone else said the port security could be an issue. But I disabled all the 802.1x/port security on one of these workstations and the problem persisted anyway.

CUCM: v10.5(2)

Phone: CP-7941G

Firmware: SCCP41.9-4-2SR1-1S

Thanks in Advance,

Matt

[Leo Laohoo]

I'd upgrade the phone's firmware first and see if it's made any difference.

[Matthew Martin]

Working on trying this today. Will comment back with results.

-Matt

[Matthew Martin]

Upgraded one of the "problem" phones and re-tested with same results.

I noticed in CUCM that the device Registration status was showing as "Rejected". But, within a few seconds of unplugging the PC from the PC Port the phone re-Registered successfully. Also, if I plug my laptop into the PC Port then the phone has no issues.

So it appears that only a select handful of these new Desktop PCs is causing this issue... I'm stumped, what could this be?

-Matt

[Leo Laohoo]

Could be an issue with the PC or the NIC card driver.  So far, there is another fellow who's seeing strange issues with this PC (LINK).

[Matthew Martin]

Yea, I'll check and see if there are any updates for the NIC and post back with my results.

Thanks,
Matt