Electrical Interference on 9508 Speakerphone - Not Echo Cancellation Issue

[jokermia]

One of my new sites has an IP Office Essential Edition, R11.0.4.0(3), 9508 phones, and POTS lines. The phones all have a feedback on the 9508 phones when using speakerphone, which would normally indicate an Echo Cancellation issue. However, at this site the EC has been turned off on both the phones and the lines, and the feedback is only when someone speaks. On the sites I've had with EC issues the feedback was constant regardless of whether or not anyone was talking. Turning EC both off and on on the phones and lines didn't help, and turning the AGC setting off on the phones for the speaker also didn't help.

I had a site in the past that had a radio station complete with tower right next door, and it turned out the radio station was interfering with the phones. This particular site has a radio station about 1/8th of a mile down the street, but I'm not sure if it would affect the 9508s or IP Office.

Any ideas? If it is some sort of interference, can you recommend something such as a ferrite barrel or line modulator that we can add to the system or phones to alleviate the feedback?

 

[jokermia]

Bump to see if anyone has come across this before

 

[budbyrd]

Is it grounded?

Dermis and feline can be divorced by manifold methods.*
*(Disclaimer for all advise given)--'Version Dependent'

 

[holdmusic34]

Attached RF inductance troubleshooting flow chart.

Also see:

https://phoneman.com/90a-attenuator.html

https://phoneman.com/modular-1-line-db-fixed-value-telephone-line-attenuator.html

These aren't instructions, only recommendations on where to source the parts once you decide which parts you may need after scientific testing.

Also, consider inductance from fluorescent lights and other sources, particularly fluorescent light starters. I had a receptionist who would only allow me to check when she wasn't there. When she would come back from her break, she would turn on the fluorescent light under the top of her reception desk and the inductance would return. It used to make her headset ring. It wasn't until i asked her to repeat the steps she takes when she returns to her desk that it was uncovered.


remembering Intrigrant 2019

 

[jokermia]

System is grounded and as far as I know there are no fluorescent desk lights affecting the phones. I'll check to make sure, though - thanks for the links as well!

 

[critchey]

Just want to be sure... the phones are 9508 not 9608 phones? This would make far more sense because by default IP phones do not play well with analog trunks and will cause quality issues. Once the trunks are "fake analog" the problem is compounded.