2. To be more Specific, the problem is only because of ISDN p2p calls. We did several test calls with different call scenarios to narrow down the occurrence and concluded the issue is only happening when the call pass through PRI Lines. Same has been tested with OTX, Group Series and RPD, no incident observed.
3. Call media encryption marked as “When available” so PSTN calls are not encrypted.
4. Customer has Group Series, OTX and HDX end points and we don't have any issue when dialing PSTN number form these endpoints using the same DMA Prefix services.
5.We have only one ISDN line on RMX and all end points uses the same for ISDN calling through DMA Prefix Dialing.
6. We are getting cracking/distortion noise for all the ISDN p2p calls and sample recording shared earlier for reference.
Centro log also attached.
For this case, Polycom tech support team RMAed the Centro main unit but even the new RMAed System has the same issue.