The modem log traces what happens during the modem connection before PPP communications are established. The modem log is enabled when you select Record Log File as part of the modem configuration procedure.
The PPP log traces setup of PPP
communications. The PPP log must be explicitly
enabled in the Registry, which you can do using the
Registry Editor utility.
Registry Editor, select Start | Run, and then run regedit.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\RasMan\PPP\Loggingkey to 1.