7921G not registering to UC520

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Dec 29th, 2009
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I am having issues connecting a 2nd 7921G to my uc520 demo kit.  i am able to connect the 1st 7921 no problem and when i copy the WLAN setup from the first phone (SSID/security) settings to the 2nd 7921G, the 2nd one wont connect.  it wont even recognize a wireless signal.  has anyone experienced this problem or do i just have a bad phone and i need to call TAC?  thanks!

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John Platts Tue, 12/29/2009 - 20:35
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The second 7921G can fail to connect if you are using an external access point, and you have your switchports or external access point misconfigured. If you are using an external wireless access point, be sure that the following is done:

  • External AP connected to UC500 switchport, Catalyst Express switchport, or ESW switchport.
  • Switchport that external AP is connected to configured as an Access Point switchport.
  • External AP is configured to allow more than one device to associate with it. This is normally allowed by default, but be sure that you are not preventing the second phone from associating with it.

I do know of one thing you can try before trying to replace your phone. You can manually upgrade the 7921G firmware by doing the following:

  • Downloading the USB Network Driver for the 7921G phone from the cisco.com website.
  • Using 7-Zip to extract the CME-Phone-Loads, UC520-Phone-Loads, UC540-Phone-Loads, or UC560-Phone-Loads TAR file from the same version of the UC500 software pack as that running on your UC520 unit.
  • Creating a new TAR containing the 7921G firmware files using 7-Zip from the extracted phone load TAR file. The 7921G firmware files need to be located at the root of the new TAR file and not in any subdirectories within the TAR file, unlike the phone load TAR files found in UC500 software packs since the 7.0.2 release. The files that need to be included in this TAR file are located in the phones/7921 subdirectory in the location where the UC500 phone load TAR file was extracted into. The files that need to be included in this TAR file if you are using the 8.0.0 software pack are:
    • APPS-1.3.3.SBN
    • CP7921G-1.3.3.LOADS
    • GUI-1.3.3.SBN
    • MISC-1.3.3.SBN
    • SYS-1.3.3.SBN
    • TNUX-1.3.3.SBN
    • WLAN-1.3.3.SBN
  • Configuring the USB Network Interface used to connect the 7921G with an IP address between 192.168.1.x (where x is between 1 and 99 or between 101 and 254) and a subnet mask of
  • Accessing the 7921G phone by going to, and then uploading the new TAR file containing the 7921G firmware files.
Steven DiStefano Wed, 12/30/2009 - 06:28
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A very thorough response sent by John, as usual.

I was thinking a very basic test would be turn off the 1st phone and try to connect from the second.

If the second doesnt work, then there is something misconfigured on that phone and time to stare and compare.

Make sure the phone load is correct, as John suggested as well.....

Steve DiStefano

Systems Engineer

U.S. Field Channel Sales team