On Fri, 28 Jan 2000 mcmahill@mtl.mit.edu wrote:

> On Fri, 28 Jan 2000, Curt Sampson wrote:
> 
> > It's actually exactly the same cable as the older Macs use, I've been
> > given to understand.

As Dan points out, not quite. Though mac-to-serial cables will work.

> FWIW, here's the pin out info I have:
> 
> so the cables are somewhat interchangable.  some of the control lines are
> different, but the tx/rx data are right.

Everything except RTS/TxD+ and Rec_clock/RxD+ are operationally the same.
The HSK[io] and GPi pins are used by our zs driver in the same way as the
Sparc RS-232 definitions for those pins. :-)

> The sparc info came from sun part number 800-5772-10, rev A, June
> 1991 "SPARCstation IPX Installation Guide", and the mac info came from
> tracing out a cable.
> 
> Serial port signals:
> 
> DIN-8	DB-25	Signal	Direction	Descr
> --------------------------------------------------------------------------
> 1	
> 
> (ipx)   20	DTR	Output		Data Terminal Ready, indicates
> 					that the computer is ready to
> 					communicate.
> 
> (mac)   4       HSKo    Output          Handshake out

Called DTR by our driver. Used either as a flow control pin (cdtrcts) on
the mac, or as DTR. :-)

> --------------------------------------------------------------------------
> 2
> (ipx)	5	CTS	Input		Clear To Send, Signal from
> 					other device saying its ready
> 					to accept data.
> 
> (mac)   5       HSKi    Input           Handshake in (can also be used for
>        					ext clk)

Used as CTS in our driver - possible presence of clocks gives our driver
fits.

> --------------------------------------------------------------------------
> 3
> (ipx)	2	TXD	Output		Transmit Data, from computer
> 					to device.
> (mac)	2	TXD-	Output		"
> 
> --------------------------------------------------------------------------
> 4
> (ipx)	7	GND	-		Ground
> 
> (mac)	7	SG	-		Signal Ground
> 
> --------------------------------------------------------------------------
> 5
> (ipx)	3	RXD	Input		Receive Data, from device to
> 					computer.
> 
> (mac)	3	RXD-	Input		"
> 
> --------------------------------------------------------------------------
> 6
> (ipx)	4	RTS	Output		Request To Send, signal asking
> 					if the device is ready to 
> 					receive data
> 
> (mac)	-	TxD+	Output		Transmit data (used in RS-422
> 					mode)
> 
> --------------------------------------------------------------------------
> 7
> (ipx)	8	DCD	Input		Data Carrier Detect, signal
> 					that indicates that modem has
> 					detected a signal from another
> 					modem over phone lines
> 
> (mac)	-	Gpi	Input		General purpose input

Used for DCD in our driver. Possible presence of clocks gives our driver
fits.

> --------------------------------------------------------------------------
> 8
> (ipx)	17	RTXC	Input		Receive Clock, not used for
> 					async devices.
> 
> (mac)	7	RxD+	Input		Receive data, (used for RS-422)