Cisco 7921, 7925 & 7926 Wireless phones hardware replacement and troubleshooting guide

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Nov 16, 2011 4:04 AM
Nov 16th, 2011

This document will help you determine whether a hardware replacement is likely to solve the problems you are experiencing with your Cisco 7921, 7925, 7926 Wireless Phones via troubleshooting advices.

Some of the below questions refer to the "Diagnostic tool" that is built in to the phone menu. This tool is available to be used as of release 1.3.4. Please refer to this link for more information on the Diagnostic Tool:  "Viewing Hardware Diagnostics" in the Cisco Unified Wireless IP Phone 7925G, 7925G-EX, and 7926G User Guide.

1. 792x Power Issues

  • If the 792x phone will not power on,      
    • may need to hold the red power button down for as much as 10 seconds
    • check with known good AC adapter and/or battery    
    • Replace the defective part (handset, AC adapter or battery)
  • If the 792x battery will not hold a charge, check with known good ac adapter and battery            
    • If the issue is the battery, then need to check to see if the battery is still in the warranty period or not

2. 792x Display Issues

  • If the 792x phone has display issues, remove the battery to power cycle the phone to see if the issue gets resolved or not         
    • If the display issue remains, then replace the 792x phone

3. 792x Keypad Issues

4. 792x Wireless Issues

  • If the 792x has wireless issues, test the WLAN via the integrated hardware diagnostics tool (need to ensure the SSID is entered in the network profile correctly; case sensitive)         
    • If successful and in range of the configured network, then available access points will be listed - this indicates that the WLAN hardware is working
    • If the SSID is correct, but no access points are visible, and if other client devices in the same vicinity can access the WLAN, then ask for a hardware replacement of the 792x phone

5. 792x Bluetooth Issues

  • If the 792x has Bluetooth issues, test Bluetooth by attempting to pair a known working headset to the 792x phone after Bluetooth is enabled      
    • If the Bluetooth headset works with another 792x phone, then ask for a hardware replacement of the 792x phone

6. 792x Audio Issues

  • If the 792x has audio issues, test the microphone, handset, headset  or speakerphone via the integrated hardware diagnostics tool         
    • If any test fails, then ask for a hardware replacement of the 792x phone
  • Reset the phone to factory default and reconfigure the phone to access the local network - if the audio problems persist, and if other phones in the same location work fine, then ask for a hardware replacement of the 792x phone

7. 792x Headset Issues

  • If the 792x has headset issues, test the headset by disconnecting and re-inserting the headset, then attempt to make a call        
    • If the test fails and the headset works with another 792x phone, then ask for a hardware replacement of the 792x phone

For non-hardware related issues, contact the TAC by raising a service request to pursue troubleshooting.


Wireless TAC issues typically include:

  • Experiencing voice gaps, 1-way or no way audio, or choppy audio
  • Experiencing roaming failures
  • Experiencing WLAN authentication failures

Voice TAC issues typically include:

  • Unable to register to CUCM
  • Unable to upgrade firmware
  • Unable to place or receive a call
  • CUCM feature issues
  • Echo while on call, noise
Average Rating: 5 (2 ratings)

Comments

George Stefanick Mon, 01/07/2013 - 10:06

I have a lot of 7925s. I can tell you the HW failure rate on these is much higher than any other handset I have worked with before Cisco or NON Cisco. We deployed 400 recently and had a 5% failure rate. Most exhibited static and poor call quality. After ruling out the wireless coverage and testing known working phones we narrowed it down to bad handsets.Once replaced with known working handsets the customer issue was resolved.

Do you have any comments or are there any known issues with the 7925 hardware wise ?

migilles Mon, 01/07/2013 - 10:16 (reply to George Stefanick)

No known hardware issues with the 7925s. 

They are also hermetically sealed with an IP54 rating to keep out dust and protect against water splashes.

I suggest that you try the built-in hardware diags tool on the 7925 phone before RMA'ing a phone.

Simply go to Settings > Phone Settings > Diagnostics, then select the component you would like to test (Keypad, Audio, WLAN).  If audio is selected then the spoken audio is looped back to the speakerphone; can switch to handset mode by pressing the speakerphone.  If WLAN is selected, then the Site Survey mode is launched.  If you don't see any APs, ensure that you have the SSID entered correctly and proper frequency band configured in the network profile.

From many engineering failure analysis performed, we have deemed a significant # as NO TROUBLE FOUND; basically a phone was RMA'd when there were no hardware issues.

So if you are getting static or poor audio quality, will want to track the audio call path (e.g. 792x to 792x, 792x to wired ip phone, 792x to PSTN, etc.) as it could be an issue with the far end device and track the location (including AP & channel) as it could be a signal related issue or due to interference or channel saturation.

Can also check the handset and speakerphone slots as well as the mic hole to ensure there is not any debris lodged inside.

And as always, ensure that the 792x phone is using current firmware.

Currently should be running 1.4(3) / 1.4.3.4 or later.

migilles Mon, 01/07/2013 - 11:06 (reply to George Stefanick)
migilles Mon, 01/07/2013 - 11:08 (reply to George Stefanick)

Glad to hear you are being diligent! 

If it is right out of the box, then more than likely is not due to any debris getting in the mic holes or speaker areas.

Also keep in mind even though I am sure you know this already, higher debug enabled on the 792x phones can impact voice quality as well (e.g. choppy or audio gaps).

George Stefanick Mon, 01/07/2013 - 11:39 (reply to migilles)

Ok, I see it .. I was blinded by the 1.4.3, didnt read the fine print to see 1.4.3.4. Any suggestions if someone was looking to upgrade if they should go 1.4.3 or 1.4.3SR1 ?

What is the difference ?

Thanks again

migilles Mon, 01/07/2013 - 16:15 (reply to George Stefanick)

Yeah we are not renumbering builds any longer like as of the 1.4(3) release.

If you have Cisco or 3rd party 11n APs then definitely want to use 1.4.3.4 or 1.4.3SR1.2 to get the fix for CSCtz75601 and CSCtn75346.

CSCtk58591, CSCtr74630, CSCtr84417 were also important fixes in 1.4.3.4.

If you have a customer using AKM mode (PSK) with Aruba APs or an AP which doesn't include the SSID in the probe response if broadcast SSID is disabled, then you will want to use 1.4(3)SR1 which includes the fix for CSCtz48689.

Other resolved caveats are minor fixes.

The 1.4(3)SR1 release was primarily to include a LCM driver update to be able to support newer hw revs.

http://www.cisco.com/en/US/docs/voice_ip_comm/cuipph/7925g_7925gEX_7926/firmware/1_4_3SR1/P256_BK_WC0078A9_00_wireless-phone-release-notes-1_4_3sr1.html#P256_TP_W908AC8A_00

You can find the resolved caveats list for 1.4(3) and 1.4(3)SR1 at the following locations.

http://www.cisco.com/en/US/docs/voice_ip_comm/cuipph/7925g_7925gEX_7926/firmware/1_4_3/P256_BK_WB14720B_00_wireless-phone-release-notes-1_4_3.html#P256_RF_R0417654_00

http://www.cisco.com/en/US/docs/voice_ip_comm/cuipph/7925g_7925gEX_7926/firmware/1_4_3SR1/P256_BK_WC0078A9_00_wireless-phone-release-notes-1_4_3sr1.html#P256_RF_R6564614_00

Going forward, please open a new thread for any software related topics as this thread is for 792x hw troubleshooting and RMA processes only.

Thanks.

George Stefanick Mon, 01/07/2013 - 10:44

Thanks for the quick reply..

Rest assured this isnt my first rodeo . In fact I had our Cisco SE onsite when I performed exactly what you mentioned. If I took the phone to other areas it still performed poorly regardless who was on the other end. In fact we were calling IP wired phones.. Once the phone was exchanged and we performed the identical test there was no issue. Introduced the problem phone again, issue reappeared. This one install we had 5% RMA run rate and they were indeed bad handsets out of the box.

A few of the phones showed on average a -6 dBm less signal strength for the same ap than other phones were showing.

Perhaps a bad batch, I dont know. But we will keep an eye on it ..

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Posted November 16, 2011 at 4:04 AM
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