THE JOY OF SERIAL CABLES

                          by Bill Graf

     When I first started playing around with projects that had 
to connect into the joystick ports of my first ATARI computer, an 
XE 130, I discovered how neat Radio Shack Joystick Extension 
Cables were they come about 10 feet long and have D9 connectors 
made on to the ends [one male and one female].  You just chop off 
the proper end, with enough cable for for your project, strip 
back the outer covering and connect up the 9 wires however you 
wish.  Now joystick ports dont use all the pins but these cables 
have all 9 wires. So when I decided to make two serial cables for 
the portfolio I naturally used extension cables Part # 270-1705, 
one reason is that they provide a nice neat connection in 
proportion to the size of the PF serial adapter.  My only problem 
seems to be I always have plenty of male ends left over.  No big 
deal since the cost is only $5.49 for the whole cable. The other 
parts needed are D25 female ends and covers Part #'s 276-1548 & 
276-1549 respectively I always use the solder type however a crimp 
type D25 connectors are available. Only use about 3 to 3-1/2 feet 
of cable to limit resistance and prevent interference [the cables 
are unsheilded but I have had no problems with them].

The wire colors are generally as follows, however, since nothing 
is certain in this world, you should always check the pin to pin 
continuity. 

               PIN 1 = BROWN
               PIN 2 = RED
               PIN 3 = ORANGE
               PIN 4 = YELLOW
               PIN 5 = GREEN
               PIN 6 = BLUE
               PIN 7 = GREY
               PIN 8 = WHITE
               PIN 9 = BLACK

NOW TO MAKE A SERIAL CABLE FOR A PRINTER OR A MODEM CONNECT THE 
THE D25 as follows:   
 
MALE D9  COLOR WIRE IN CABLE connect to  FEMALE D25 PINS* 

PIN 1 = BROWN ---------------------------->PIN 8       ALL
PIN 2 = RED ------------------------------>PIN 3  
PIN 3 = ORANGE --------------------------->PIN 2       OTHER
PIN 4 = YELLOW --------------------------->PIN 20
PIN 5 = GREEN ---------------------------->PIN 7       PINS
PIN 6 = BLUE ----------------------------->PIN 6
PIN 7 = GREY ----------------------------->PIN 4       LEFT
PIN 8 = WHITE ---------------------------->PIN 5
PIN 9 = BLACK ---------------------------->PIN 22      EMPTY
 
* Some applications will need a gender changer or a male D25 
could be substituted.


NOW TO MAKE A NULL MODEM CABLE TO CONNECT THE PORTFOLIO SERIAL 
PORT WITH AN ST, MEGA, OR AN IBM or COMPATIBLE PC or XT CONNECT 
THE D25 AS FOLLOWS:
 
MALE D9  COLOR WIRE IN CABLE connect to  FEMALE D25 PINS

PIN 1 = BROWN  (NOT CONNECTED AT ALL)                      

PIN 2 = RED ------------------------------>PIN 2  
PIN 3 = ORANGE --------------------------->PIN 3              
PIN 5 = GREEN ---------------------------->PIN 7

                                                            
PIN 4 = YELLOW -------------)              PIN 4----)
          & connect together|                       | jumper wire
PIN 6 = BLUE ---------------)              PIN 5----) connect 2 
                                                      pins 

PIN 7 = GREY ---------------)              PIN 6----)         
          & connect together|                       | jumper wire   
PIN 8 = WHITE --------------)              PIN 8----) connect 3 
                                                    |  pins
                                           PIN 20---)
PIN 9 = BLACK  (NO CONNECTION AT ALL)           

That's it, put the hoods on the D25's and you're in business,BUT,
check the connections with an ohm meter or battery and bulb 
circuit tester before to try it, No guarantees if you blow up 
your gear, but it works for me! ..........Bill Graf 

GEnie E mail  ABGRAF