[Coco] CoCo to Apple //e serial card NULL MODEM

[Willard Goosey]

>Date: Sat, 20 Dec 2003 00:36:25 -0600
>From: Perry M Dueck <pmdueck at shaw.ca>

>2. Anyone know how to construct a null modem cable which would hook up a
>CoCo serial port to an Apple //e super serial card serial port (25 pin
>connector).  I realize that I would need a 4 pin round DIN male plug for
>the CoCo and a DB25 pin male plug for the //e serial card, but which wires
>would go where for proper null modem communication between the two
>computers?

Assuming the //e has a standard pinout on its serial port, this should
do it:

RS-232 Cabling for the CoCo


function  CoCo DIN
CD	  1
Recieve	  2
GND	  3
Transmit  4

	  Typical DB-25
Transmit  2
Recieve	  3
RTS	  4
CTS	  5
DSR	  6
GND	  7
CD	  8
DTR	  20

CoCo to DB-25 straight through

Func  DIN  DB-25
CD     1     6
RD     2     3
GND    3     7
TD     4     2
	     4-5	This means tie these lines together.

CoCo to DB-25 Null Modem Cable

Func  DIN  DB-25
CD     1     20
RD     2     2
GND    3     7
TD     4     3
	     4-5


I've never built the null modem version, but used the straight-through
model, and the null modem cable is what I'd get hooking a null modem
to my cable.  YMMV.

>
>best regards, Perry
>
Willard
-- 
Willard Goosey  goosey at sdc.org
Socorro, New Mexico, USA
"I've never been to Contempt!  Isn't that somewhere in New Mexico?"
   --- Yacko