I believe that by default for a dial in account that would be in /etc/chatscripts/provider, together with the other chat tokens (phone number, modem initialization string and some more).
--- Begin Message ---
Hi,Does anyone know where the user name and password would be for your isp ???I thought it was the ppp file, ?Does anyone know ?
--- End Message ---
Shaul Karl email: shaulka(replace with the at - @ - character)bezeqint.net