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		RS232 pinouts (from inmac breakout box)
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PIN*   NAME   T<->C	FUNCTION	* means commonly used
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1	FG	.	frame ground
2*\	TD	>	transmitted data
3*/	RD	<	received data
4*\	RTS	>	request to send
5*/	CTS	<	clear to send
6	DSR	<	data set ready
7*	SG	.	signal ground
8*	DCD	<	data carrier detect
9	+	<	positive dc test voltage (binary 0, space, on)
10	.	<	negative dc test voltage (binary 1, mark, off)
11	.	.	unassigned
12   (s)DCD	<	secondary data carrier detect
13   (s)CTS	<	secondary clear to send
14   (s)TD	>	secondary transmitted data
15	TC	<	transmitter clock
16   (s)RD	<	secondary received data
17	RC	<	receiver clock
18	.	>	receiver dibit clock
19   (s)RTS	>	secondary request to send
20*	DTR	>	data terminal ready
21	SQ	<	signal quality detect
22	RI	<	ring indicator
23	.	>	data rate select
24     (TC)	>	external transmitter clock
25	.	>	busy
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Notes:
- Trailblazers want RTS asserted (space) or they don't play if using RTS/CTS
  flow control instead of XON/XOFF.
- DTR is normally asserted (space) and drops for 1/4 second at hangup
- The idle state of TD is mark, so a start bit is space and a stop bit is mark
- some terminals won't send anything if DCD is off.  You want the modem on
  the computer end to generate a hup when disconnected (&c1), but the terminal
  end to always assert DCD (&c0).