We're working on a new deployment that we're putting in production in less than 2 weeks and we've hit a bump. We are running 6921's, 7940's, 7942's, 7962's and 7937's. Call quality on the 7940's are phenominal while the 7942/7962's are horrible. There is a tunnel sound w/ a clicking sound going on. We've updated the firmware and then downgraded trying to get through this.
If we put a 7940 in its place, the call quality issues goes away. Any ideas?