Prior to this change, in order to send one command to a printer the XL had to execute the following commands with a 6370. Each command requires the XL to wait for a response from the 6370

1. Clear the RS232 Receive Buffer
2. Send Print Message data.
3. Tell the 6370 to send it to the printer.
4. Ask the 6370 how many characters it has received from the printer
5. Ask at least one more time to make sure the printer has stopped sending.
6. Request the printers response from the 6370.

The protocol and communication has been changed for newer 6370 boards v3.04 to require fewer commands and less time waiting on responses.

1. Clear the RS232 Receive buffer, send the Print message Data to the 6370 and the 6370 starts sending it right away.
2. Request how many characters the 6370 has received from the printer. If the printer has received enough characters and has not received any more in some time, also return the characters to the XL.

The actual 6370 protocol has been updated and more details can be seen in the 6370 protocol spec. The XL has been updated to use the new commands so that it can spend less sending commands and waiting on responses.