>Thanks - I can understand why you made the comment, the problem may be specific, but some of you're suggestions are generic to comms problems (I was going to ask if the DEC end was configured for XON/XOFF handshaking - if not any XON/XOFF may be causing the problem, but I got sidetracked before I added it to my post).

I still have a couple of outstanding questions to John about the DEC configuration. I do believe he is looking at handshaking and/or buffer overrun problems. Your observation may prove to be correct.

>I've had many problems in the past with 3rd party comms routines, one caused by buffer overflow in a Unix system, where the condition wasn't flagged, the buffer was simply emptied & refilled. Since then I've always preferred to be in total control of comms routines, writing my own in asembler. Now I'm in a position where I must consider using ActiveX controls, I want to know all the pitfalls I might run into, as some of the comms. is in safety critical areas.

Assembler? Yikes! If I have to deal with any amount of data, I try to stick with VFP. If it is more of a controller type of app, I do it in VB. It just seems to go easier and the choice of controls out there is very broad. At present I'm experimenting with a combination of the two, just to broaden my knowledge.