Starting somewhat randomly across multiple chassis with no software updates or hardware changes in ages we've had DSPs taking modems and the corresponding T1 B channels out of service. This occurs on all DSPs (8) and takes out modems at a rate of roughly 1 per hour. The only cure seems to be resetting the DSP cards. DSP software is 2.1.9. In addition some cards have started causing packet bus failures with the ARC sysloging the interfaces appearing and disappearing. We've checked with our telco and have corrected a translations problem that was preventing service messages from properly removing the channels from service; however our equipment continues to place channels in 'LOCAL OOS' local out of service state. Swapping and replacing cards has generated no change in the condition. In additon we've seen some DSPs generate the following on the console: (Ch.10): 19:29:47:044 DSP Fatal Error: Parm = 94 Does anyone have an ideas as to what could be the root cause of failure? Could the backplane/midplane be failing somehow and causing all of the DSP errors? This system has ran flawlessly for at least 2 years and all of a sudden everything is going to hell. Thanks... Thanks, Kurt GTI X2 x2@gti.net