Router - TG582N - PPP Settings
Changing PPP Password, via telnet CLI
The command to use is essentially:
:ppp ifconfig intf=Internet user=x@a password=secret status=enabled
However one can't ppp ifconfig an interface which is administratively up, so one would have to actually do:
:ppp ifdetach intf=Internet :ppp ifconfig intf=Internet user=x@a password=secret status=enabled :ppp ifattach intf=Internet