Pin	Func.	SDR Function

1	DCD	PTT
2	RXD	Not used
3	TXD	Not used
4	DTR	Keyer common high
5	SG	Ground
6	DSR	Dit
7	RTS	Tx
8	CTS	Dah
9	RI	Not used

DTR is set high by the software.  Drop down resistors (value 4.7k) are connected between DTR and DSR/CTS.  This allows the paddle to short the voltage without damaging the serial chip.
