I've been getting multiple TRK 136 errors (rls. failure in incoming trunk; status changed to lockout). Incoming callers can't hear us but we can hear them. Carrier said there was a problem in their network two days ago which they've since repaired, but problem still happening. Can this one-way transmission problem EVER be CPE-related? T1s are all up and no errors (counters all zeroes). thanks.