What do you call using an .OCX file? It's just somebody else's code, but in this case, it's really old school code. I have to congratulate you on wanting to write your own class for Serial Comm. It's the best way to learn and to get all the features you want. RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Kyle Edwards wrote: even after GC.Collect() on then next line Don't call the GC Collect method unless you specifically know what you doing and why. When the GC Collects, it has to wait for ALL threads running under the .NET Framework to pause. This CAN take a LOOOOOOONG time to do. Only when all the threads are paused can the GC safely do it's job. When it's done, all the threads are resumed. RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome