Digi Acceleport 8p


we have a Digi Acceleport 8p on a Microsoft Windows 2003 Server R2.

The communications are good beetwen the server and a remote PC using Hyperterminal.

We have our own visual c++ communication program.
We don’t have problems with emission: the remote pc receive all characters whe sent.
We have some problem with reception : we only receive 4 characters.

This program use the readfile command without the overlapped parameter. It work on a NT4 server with a Digi com8i.

Thie same program work on 2003 server with the serial ports on the motherboard.

why do we received 4 characters with digi serial ports when whe received all characters with on-board serial port using the same c++ program ?

Is there some buffer difference ?

Thanks for your help

Message was edited by: DMS


If you are comparing the AccelePort 8p (PCI type) to the Com/Xi (an 8 bit ISA type), there are differences too numerous to detail. Yes, there are much bigger buffers for the 8p, AND they are dynamically re-allocated, so they are not a set size.
Please make certain that you have the latest driver installed (version
Do you have the option complete write when sent enabled for the port you using?

Thank you for your answer Async-man.

The driver is the lastest one (
the complete write when sent option is disabled.
Does it matter if the complete write when sent option is not enabled in receive mode ?
I will test this option today.

The Readfile function doesn’t work without the overlapped feature. I have quite found the answer.


I found the solution.
The problem wasn’t the Readfile function.
It was the of hexadecimal for XON and XOFF anstead of integer.Indeed, Windows 2003 doesn’t use the same number of bits as Windows Nt does : the conversion from hexadecimal to integer doesn’t give the same result between the 2 platforms with the same c compiler.

The problem is solved.
Thanks for your answer.