I have not purchased the board yet - we will be purchasing 2 of these boards for 2 separate PCs. These 2 PCs will be sending data back and forth to each other in real time to create high speed printer data (410 pages per minute). My question is this - if the 1st PC is sending data to the 2nd PC and the buffer gets full - would the 1st PC get a message that the buffer is full?
This is what is typically known as flow control. As long as you have some type of flow control enabled on your serial ports (and it matches the devices attached to the serial ports), this should work.
There will be a number of articles in our knowledge base which discuss flow control, both in general and specifically related to Operating Systems. Please let us know which OS you’ll be running on the PCs these cards will be installed in if you have problems finding information about flow control.