You cannot copy directly to tape, you'll need NTbackup.exe for it.
All backup operations can be performed at the command prompt using NTbackup. NTbackup.exe utility in NT can be used as GUI and can also be incorporated in a batch file with appropriate parameters. Most of the command parameters do not require user input.
Keep in mind though, using batch files enables you to back up directories only (not individual files). Wildcard characters cannot be used in the batch files.
For more help on command line parameters, just run the utility and see help on "batch files".
Hope this helps.
Mubashir