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Screeching/Crackling Noise with 7940/7960 over FXO Lines

Hi all,

I've been experiencing this strange issue for some time and so far I've not been able  to find the fix for it. Hoping someone can help !!!

I am running CCM 4.1.3 with 7940 and 7960 phones, The issue I've been experiencing is that when I talk on speaker over an FXO line to an outside call. I notice this screeching/crackling noise when I talk. It only happens when I am speaker and it seems to get worse when I talk louder. This has been an ongoing issue and it happens at all locations where I have analog lines with FXO card.

Has anyone run into this issue before ? I appreciate any inputs / suggestions.

Thanks in advance !!!


  • IP Telephony
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