Part of the Basic Connectivity Set provided by Apple. These tools are automatically installed and used by terminal emulation software. You have probably installed MacTerminal 3.0 or a third-party terminal emulation software package that has licensed the tools from Apple. This tool establishes a direct connection using the serial port. It also specifies connection settings for modems that are not Hayes-compatible. If you do not or will not work with telecommunications over a network or the Internet, you do not need this extension.