Andy
I've been thinking about this again and i came to this conclusion:

1. You can write your own driver for the 16550 chip of the pc to keep track of the parity error to deduce your 9th bit.

2. cport library keeps track of the last error, you can try to modify it to keep errors in error array and not to override the previous error as is the case.

3. you can buy a serial port card for the pc that supports 9 bits and modify the cport library(much less work than step 2)

4. you can send your data as a bunch of 9 bytes, the first 8 would be first 8 bits and the 9th byte would contain the 9th bit for each byte (byte stuffing).

Mahmood