Peter:

>You don't see any XON/XOFF because they are handled by the MacOS. I suspect
>that the external device is sending an XOFF to your Mac and that possibly
>it is never sending an XON to restart comms.

That would explain a lot. For example, the timing of my sending data to the
device is not linear. There are significant periods of waiting while the
device digests its received file and burst of rapid data transmission of
small files. And, my Mac just sits and waits during the slow periods and
accommodates the burst in stride. Now, I programmed my Mac to be fast in
sending data, but I didn't program my Mac to wait. But, then again, my Mac
often does what it wants regardless of what I tell it to do (kind of like a
wife). So apparently, my control over things is limited.

I suspect that the problem is not XON/XOFF related. After all, it handles
the sending of numerous large files without problem. The problem only
arises when the device interrupts the flow by sending an abort command
while digesting a large file. And, this is also compounded by the fact that
this abort command is received successfully at all other times except for
the large file digestion. Go figure.

So, I guess the question is: "How do I get around, or turn off, this MacOS
'feature'?". Should I turn off the XON/XOFF and try to do it on the fly?

tedd

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