I've put together a short text file explaining it. The general idea of it is that the 6551 chip used in the RS232 Pak is inadequate for modern high speed modems. This modification corrects some of the problems this chip has and also adds the extra capability of hardware handshaking between the RS232 and the Modem.
This hardware handshaking makes high-speed communications painless by making the chip send back it's status to the modem. The big benefit is that you can take a lot of work away from the CPU & 6551 chips and place it onto the Modem! With it, you can communicate at 19200 (or even 38400) baud without losing incoming data - EVEN if your 'halt' disk controller is running!
RS232 Pak Data | Want to use the RS232 Pak in your own programs? Here's the data you need | |
rs232mod.txt | Notes about adding hardware handshaking and other modifications to the CoCo's RS-232 to increase hi-speed performance | |
rs232mod.gif | 640x400 diagram of my RS232 hardware handshaking modification |