Pinouts on the Archimedes machine
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Name:     0310032
Version:  0.02
History: 
  0.01:  Undated  :  started.
  0.02:  14-Feb-89:  updated for release on SID


The following diagrams show the connectors as viewed from the outside of the
case.

1. THE VIDEO CONNECTOR 
----------------------

This is based on a 9-way D-type socket connected as follows:


  ________________
 |                |
 | 5  4  3  2  1  |
 \                /
  \  9  8  7  6  /
   \____________/  


       1       Red
       2       Green
       3       Blue
       4       Composite sync (Horizontal sync*)
       5       NC (Vertical sync**)
       6-9     0v


*  The output from pin 4 depends on the position of PCB link 10.         
** The output from pin 5 depends on the position of PCB link 11.

Note: Pin 5 may also be allocated, optionally, on future production for
SCART Blanking PULL-UP, so that the Archimedes machine can be used with
SCART input TVs.


2. THE ECONET CONNECTOR 
-----------------------

This is a 5-way 180 degree DIN socket.

       _______
      /       \
     /         \
    | 3       1 |
    \   5   4   /
     \    2    /
      \_______/


The Econet system works by using the voltage difference between two lines.
For this reason it has two data lines (one positive and one negative) and
two clock lines.

       1       Data positive
       2       0v
       3       Clock negative
       4       Data negative
       5       Clock positive


3. THE PARALLEL PRINTER CONNECTOR 
---------------------------------

A printer lead suitable for an IBM PC or compatible can normally be used
with the Archimedes machine.

However, if you want to make up your own lead, the 25-way D-type socket is
shown below.                                                              


      ____________________________________________________
     |                                                    |
     | 13  12  11  10  9   8   7   6   5   4   3   2   1  |
     \                                                    /
      \  25  24  23  22  21  20  19  18  17  16  15  14  /
       \________________________________________________/



The pinout of the connector runs as follows:

               ___
       1       STB     Strobe line to printer 

       2       D0      Bit 0 of the data
       3       D1       "  1  "  "   "
       4       D2       "  2  "  "   "
       5       D3       "  3  "  "   "
       6       D4       "  4  "  "   "
       7       D5       "  5  "  "   "
       8       D6       "  6  "  "   "
       9       D7       "  7  "  "   "
               ___
       10      ACK     Acknowledge line from printer 
       11      BSY     Printer busy

       12-16   NC      Not connected 
       17-25   0V      0V           


The shell of the socket is connected to groundshield.


4. THE SERIAL PORT
------------------

The serial port uses a 9-way D-type plug as shown below.

  ________________
 |                |
 | 1  2  3  4  5  |
 \                /
  \  6  7  8  9  /
   \____________/


The pinout of the connector is as follows:

        1       DCD     Data Carry Detect
        2       RXD     Receive Data
        3       TXD     Transmit Data
        4       DTR     Data Terminal Ready     
        5       GND     Ground Return (0V)
        6       DSR     Data Set Ready
        7       RTS     Request to Send
        8       CTS     Clear to Send
        9       RI      Ringing Indicator


For more detailed information (on connection to other computers, modems,
printers etc.) refer to Issue D of the Archimedes serial port application
note, accessible on SID: document number 0310052.