INT 14 - COURIERS.COM - SEND SINGLE CHARACTER                                   
	AH = 89h
	CL = character to send
Return: nothing
SeeAlso: AH=01h,AH=84h"COURIERS"
                                                                                

INT 14 - COMM-DRV v14.0 - TURN ON RTS                                           
	AH = 89h
	DX = port number
Return: AH bit 7 set on error
	AH bit 7 clear if successful
SeeAlso: AX=8000h"COMM-DRV",AH=87h"COMM-DRV",AH=8Ah"COMM-DRV"