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Defining the Serial Interface

Consult your system Owner's Guide for complete information on your system's serial ports. There are two types of serial interface equipment available: Data Terminal Equipment (DTE) and Data Communications Equipment (DCE). The primary difference between DTE and DCE is the use of several pins on the connector. For example, DTE devices output on pin 2 and input on pin 3. DCE devices output on pin 3 and input on pin 2. You can connect a DTE interface directly to a DCE interface.

To connect either a DCE to a DCE or a DTE to a DTE, use a null modem cable. A null modem cable allows equipment interfaces of the same type to be connected by swapping the appropriate input and output pins.

Silicon Graphics provides three special files that determine the signals that are used on each port. The special files beginning with ttyd are used for devices such as terminals; ttymX files are used for modems that do not use hardware flow control; and ttyfX files are used for devices that can use hardware flow control on the RTS and CTS pins.



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