Hi Don, If you have a moment, what does "serial port exclusive open" mean in MLDX 4.2.3? I have a fairly brittle serial port situaton with my K2/MLDX/CocoaModem setup -- nothing to do with MLDX, which is doing its job just fine. I just wanted to make sure I understood this feature before installing 4.2.3. Thanks and 73, Ken K3VV Coopersburg, PA