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Static when far end caller is NOT speaking - 4224 PRI

Hi all,

Have a working 4224 installation that has the following issue. Occasionally on inbound and outbound calls, we hear bursts of static that cease immediately when the far-end (PSTN) caller speaks. Later, the static will begin again, only to cease when the far-end caller speaks again. The static does not begin or end based on our (IP Phone) speaking, nor does it seem to have any correlation to the quietness of the far-end caller. For instance, if the far end caller mutes their phone, the static may or may not come back. If it does, when the far end caller speaks, it immediately stops again. BellSouth PRI, VWIC 1-MFT-T1. This weekend the carrier did a lengthy (1 hour) loopback stress test through the CSU/DSU and found no issues.

Any ideas? I have opened a TAC case and am working it through them, and will post the fix when / if, but wanted to ping the collective.


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New Member

Re: Static when far end caller is NOT speaking - 4224 PRI

I had the same problem after upgrading a 4224 to VIC-FXO-M1 (caller-id) cards and upgrading the IOS. I removed the M1's and returned the IOS to a lower revision and the problem went away. You may try an older revision of the IOS if possible.