It\'s actually an extra everything inside the french speech marks << >> ;-):
<< ~ \'\' >>
The double single quotes are required (as the chatscript is all on one line..., etc.).
This sits on the end of the first line of the script which lives in /etc/ppp/peers, on the end of the bit which starts /sbin/chat (from memory).
This tells chat to wait for a tilde, then reply with nothing before handing over control to pppd. My uni allows both manual terminal and automatic ppp logins and if I don\'t do this my Z seems to start pppd too soon and then the uni end thinks I want to login manually so it just sits there authenticating forever then quits.
Also note the bit about chap and pap as this caused me a load of headaches until I realised what was going on.
Si