You can create a chat file that is an executable script to be run automatically when the dial-up link is initiated. Thus, you can run additional commands, such as stty for parity settings, besides those that are contained in a traditional chat script, during link initiation.
This executable chat script logs in to an old-style UNIX system that requires 7 bits/even parity and then changes to 8 bits/no parity when running PPP.
#!/bin/sh chat "" "AT&F1" OK "ATDT555-1212" CONNECT "\c" stty evenp chat ogin: pppuser ssword: "\q\U" % "exec pppd" stty -evenp |