NAME:		RXD

SYNTAX:	RXD < ON | OFF >

DESCRIPTION:

     This command tells the serial module to start/stop listening to
     the serial port. When not listening, the characters coming in will
     be lost if no other program is listening. The purpose of this
     command is to allow another program to use the serial port directly,
     as long as the other program opens the serial port in shared mode.
     Properly written programs will do this, and don't let anyone tell
     you different.

     If two or more programs are sharing the serial port, and if they
     all have read commands pending, incoming data will be split between
     them, usually in arbitrary amounts ranging from 1 to several hundred
     characters. Be sure to turn RXD OFF if any other program is loaded
     and using the serial port.

EXAMPLES:

       RXD OFF
       RXD ON

NOTES:  Turn RXD off too long without another program 'taking over', and
        you will lose data.  You cannot open the serial port with exclusive
        access while sermod is running.