pppd and autoconnect

using phdialer works fine to get a ppp connection with a modem
From what I understood reading the docs, it should be also possible
to do this automatically and without starting photon.
If tcp/ip gets a request and has no route it should start the
script (if AUTOCONNECT =1 is set).

Q1: Are ther some additional settings necessary for autoconnect?
Q2: Is there an example available for a chat script? using a modem or isdn

Thanks for some help Werner