Microsoft Windows NT, 2000, XP provide very useful utility to manage RAS-connections from the command line. It can be used to establish remote (dial-up) connection and to terminate it from BAT-script. Windows 95, 98 and Me have not such utility.
RASDw9x is designed specially for Windows 9x and Me, but it works with Windows NT/2000 fine too. It allows to get a list of available RAS-connection entries, to open specified RAS-connection and to close specified or all active RAS-connections from the command line. Each time it returns a termination code to the operation system.