We have a carrier that we receive calls from over SIP. They are getting the call from the PSTN and then sending to us as sip. We then get other calls to our FS via sip from other carriers that are also from the PSTN. We bridge these calls in FS. All connections to FS are sip. So. Party1--PSTN--Carrier1--FS--Carrier2--PSTN-party2 Problem is that Party2 hears echo of themselves. We chased it down and Carrier1 says it is because Party1's carrier is setting a bit in the ss7 connection that they are doing echo cancel (when in fact, they are not). So Carrier1 does not do any EC on the call before passing it to us. Is there any way that I could do the EC on this call in FS?
From what I have read on the list, it looks like the Zaptel Hardware or OSLEC type of EC would not work here since there is no zaptel/t1 connection involved with FS.