Here's how to install MacTerminal 3.0 on System 7.x:
The Installer on Disk 1 of the MacTerminal 3.0 package installs the
Macintosh Communications Toolbox. Since the Macintosh Communications
Toolbox is built into System 7.x, you don't need to run the Installer.
1) Remove the Communications folder you created manually. In System 7.x, the
Communications Tools reside in the Extensions folder in the System Folder.
Drag these Tools from Disk 2 directly to the Extensions folder, or to a
closed System Folder, and System 7.x will put the Tools in the Extensions
folder.
2) Create a new folder called MacTerminal 3.0 on your hard disk, and
drag the MacTerminal application and sample session documents from the
MacTerminal disk to this new folder.