APU-72 EHS intermittent disconnect issues on Cisco 8961/9971 phones

[john.chatman1]

I have an odd issue that I cannot resolve. I have five Plantronics CO54-XD wireless headsets connected to four Cisco 8961 phones and one Cisco 9971 phone. I have them connected using a Plantronics APU-72 Electronic Hookswitch cable (EHS). All five phones exhibit a behavior where, at random times during the day, the phones display and error message that "The Plantronics APU-72 has disconnected". After 4-5 seconds, another message appears stating that "The Plantronics APU-72 has connected". During the 4-5 seconds that the connection drops, neither party in the call can hear each other, but the call does not drop. I have updated the firmware on all five phones to the latest version (sipxxxx.9-4-2SR2-2). I have also tried downgrading to a couple of older firmware versions (sipxxxx.9-4-1-9 & sipxxxx.9-3-x-x), but the issue has not been resolved. These phones do not support the "Headset Hookswitch Control=Enabled" option. Instead, their "Enable/Disable USB Classes" option must be set to "Audio Class" in CUCM. I have done this on all five phones and verified that setting on the phones as well. Still the problem remains. These phones are used in a call center environment so this issue must be resolved for quality management. Plantronics support was unable to help us and blamed the Cisco firmware. We upgraded the firmware at their request, but it obviously did not solve the problem. Has anyone else experienced this issue or found a resolution? I would greatly appreciate any assistance as I am banging my head on my keyboard at this point. (john.chatman@iceomatic.com)

[Ben Heller]

Did you ever find a resolution for this? We have some 9971's connected to C053 headsets with the APU-71 cable with the same problem. It seemed to just recently begin to happen when the phones firmware hasn't been upgraded in a few months.

I use a Jabra headset on my 9971 and have had no issues.

[john.chatman1]

So far we have not found a resolution. We tried other APU-72 cables in case we had a bad batch but that did not resolve the issue. After contacting Cisco support and Plantronics support, we are no closer to the answer as they just point fingers at each other. We ordered a couple of Jabra headsets and EHS cables to test and if they work, we will likely replace the Plantronics headsets. We updated the Cisco 9971 and 8961 phones to the latest firmware and also tried going backwards one firmware revision but the issue was never resolved.

[Ben Heller]

For quite some time it seemed to have stopped and no one was having issues. Then a month or so ago it started to happen off and on again. We got new cables from Plantronics but it didn't seem to make a difference and phone firmware doesn't seem to matter.

Out of an office of 10-15 people using the same phones and headsets only maybe a third or so are experiencing the issue. I personally don't use the USB cable at all and just manually swap to headset port and never have any issues, however there are others who use the cables (some which are years old) and don't ever notice the disconnect alerts.

Most likely we are going to move to a different phone model, especially if you are seeing the same issue with Jabra headsets. We luckily only have a few users experiencing the issue and not too many phones total so it is likely the better option over trying to experiment with different headsets and firmware since nothing seems to help.

[john.chatman1]

We have not found a solution to this as of yet. We are getting the same issue on the Jabra Pro 9460 headsets with Jabra Link EHS cables. Further investigation has shown that "babble" on the USB port is the cause, but we cannot find the source of the "babble". We have updated the firmware on the APU-72 cables and on the Cisco 8961/9971 phones but to no avail. Cisco's standard firmware for these phones will allow up to 3 instances of this babble before resetting the APU-72. Cisco was able to provide a custom firmware that allowed up to 300 instances of the babble, but it proved to be ineffective. We are researching other phone, headset, EHS cable options to see if we can get away from the USB ports on these phones. So far we are no closer to finding the solution. Have you had any luck? I would appreciate any insight into a resolution to this issue.