[USR-TC] DSP Calls Not Dropping Past Channel 9

have users complaining about busy signals, when checking the connections, it looks like no calls get past channel 9 ever, and during peak times, customers are experiencing busy signals. This just started all of a sudden with no changes on the Chassis, or the configuration of any of the cards. We have a single DSP, Single HiperARC Can anyone give me a clue of what to search for on this? Thanks, Rodney