Deducing Switch settings FAQ
----------------------------

(2nd March '95 John Keay)

How can I find out the switch settings for game X?

1) Look in the cabinet.

Many games have lists of switch settings in the cabinet, or
on scruffy bits of coffee stained paper thrown in the bottom of
the cab.

2) Look on wiretap.spies.com

The directory /pub/game_archive/switchSettings has lots of
useful switch settings.

3) Figure them out from scratch.

This is the fun part. How can you do this without it taking
forever (and without destroying you power supply and game
board in the process).

Firstly switch settings are often only resampled at reset
(or sometimes on leaving test mode) so usually you will
have to power the game on and off to try various combinations.

 a) Test mode
   This is the easy one. Often boards have built in test modes
   that will allow you to play with the switches and will
   automatically translate the switch settings into "English"
   and display the info on the screen.

   Of course you will need to know which switch (or pin) puts
   the board into test mode. This is sort of a circular problem
   but see below.

 b) Reset button
   Powering a board on and off again and again will not do the
   board and the power supply any good, so if the board has
   a reset button, use it.

 c) Test mode (revisited)
   Sometimes the board may resample the switch settings as it
   leaves test mode. In cases where the test mode doesn't give
   you any clues this feature can be used to avoid having to
   power the board on and off. AS I SAID YOU SHOULD DO ANYTHING
   TO AVOID POWERING UP AND DOWN LOTS OF TIMES, AS THIS MAY
   DAMAGE YOUR BOARD/MONITOR/POWER SUPPLY.

 d) Look for a test mode switch
   Make a note of the current switch settings (because they
   my be good defaults), power the board up and change
   the position of ALL the switches. If nothing changes
   reset board. If a test mode switch exists you will
   now probably be in test mode. If a switch exists
   to flip the screen over you may well find it at this
   stage.

 e) Pause switch
   If you flip the switches over and the board doesn't
   power up correctly you may have changed the pause
   switch. You will have to use the techniques below
   to locate this switch before you can proceed.

   As an aside, have you ever received a new board
   with the pause switch set? If you ever get a board
   that doesn't work always try flipping the switches
   and powering up again. The pause switch may be on
   and/or the board's test mode might help debug.

 f) Try different combinations of switches.
   Lets say you have 16 switches, well that is _ONLY_ 65536
   different combinations! Fortunately most function are
   controlled by a single switch and if you do things
   right it should only take 4 tests to find any single
   switch function (for our 16 switch example).

   The key here is 'binary search'. The process might
   be obvious to folk out there (esp. anyone who has
   spent too long in front of a computer), but here it
   is in writing. Lets say our initial 'flip all the
   switches over' test confirmed the existence of a
   test mode and we want to find out which switch
   controls it.
   Split the switches into 2 equal groups 'A' and 'B'
   and change the state of all the switches in group 'A'.
   Reset the board. If this effected the board entering
   test mode then the test mode switch is in group 'A'
   (so we can ignore group 'B') if not then we can
   concentrate on group 'B' (and ignore group 'A').
   Either way we now only have half as many switches
   to worry about. We simply repeat this process until
   we know which switch controls test mode.

 g) Switch priority
   Certain switches over ride others (for example a 
   pause switch will usually over ride test mode).
   So you may have to locate higher priority switches
   before you can find the lower priority ones. i.e It's 
   no good looking for a cocktail/upright switch until
   you can avoid pause and/or test mode switches.

 h) Common switches
   Dip switches are used to control all sorts of functions
   here are a few of the more common ones.

   Pause            - Usually highest priority - stops the game
   Test mode        - Usually 2nd highest priority 
   Cocktail/Upright - In Cocktail mode player 2 will be upside down
   Screen Invert    - You often don't need to reset the board
                      to find this. Not to be confused with
                      Cocktail/upright
   Starting lives   - Press player 1 start and count the lives
   Bonus lives      - This info is often written on attract mode
                      screens (often multiple switches)
   Language         - The attract mode screens often show this.
                      (usually multiple switches)
   Difficulty       - Usually the hardest settings to guess. If
                      anyone has any fast methods of finding these
                      I'd be interested. (usually multiple switches)
   Credits/Coin     - Sometimes all these switch on gives
                      free play (usually multiple switches)
   Free Play        - Sometimes free play has it's own switch
   Demo mode sound  - Do you get sound in attract mode?
   Continue enabled - Does the game let you continue after
                      you have died. Sometimes multiple switches
                      control how many times you can continue
   Cheat mode       - In some games this switch stops you
                      from loosing lives and can be used
                      for play testing.
                    
4) Ask the net

If all else fails you can drop a line to the net in the hope
that some lazy so and so, has the switch settings but hasn't
sent them to the archive yet. ;-)

Regards, John.

* John Keay                               ! Texas Instruments Ltd. *
* work: keay@tiuk.ti.com                  ! Bedford, U.K.          *
* home: john@keay.demon.co.uk             !                        *
* Disclaimer:  All opinions expressed herein are personal. etc etc *