I am using OPEN "C" commands and finding it is extremely slow to open 
and close a serial port in OS X with a keyspan usb serial adapter.  It 
takes a second to open, print 40 characters and close at 9600 baud.  It 
doesn't seem to be the printing taking the time, it appears to be the 
Open "C"

I also found that if I placed a DELAY statement after a PRINT# 
-g_serialport , it will not print. If I wait to long, it is as though 
the port has been closed down.  Its not the delay statement itself, as 
kind of delay, would cause it not to work.

In OS 9, I could open the serial port, print and print, leave the port 
open, print some more, wait, print, etc. Not in OS X.

It appears flow control isn't working too, as I can easily overflow my 
printer buffer and loose communications. I have to check the cable, as 
I have several, but I don't think it is that.

Anyone else have experience this with a Keyspan and using Open "C" 
command in OS X?

~ stev