AMT1

THIS IS A FILE EXPLAINING MODIFICATIONS TO THE AEA AMT-1 AMTOR
TERMINAL UNIT IN DETAIL. SOME ARE FOR CONVENIENCE OTHERS MAKE IT
WORK BETTER.  SOME ARE FACTORY AND SOME ARE MINE.
FIRST THE LIST OF CHANGES:
  1) REPLACE FILTER RESISTORS. (FACTORY MOD)  2) REPLACE R5. (FACTORY MOD)  
3) REPLACE C1.  4) MODIFY DISPLAY LIGHTS.  5) ADD POWER SWITCH.  
6) ADD TX DATA INVERT SWITCH.  7) ADD RX DATA INVERT SWITCH.  
8) ADD PTT KILL SWITCH.  9) ADD AUDIO I.O SHORT SWITCH. 
10) ADD TTL/RS232 SELECT SWITCH. 11) ADD RS232 I/O JACKS. 
12) ADD TRANSMITTER TTL OUTPUT JACK. 13) SEPARATE ANALOG/DIGITAL 
GROUNDS (FACTORY MOD-ONLY NEEDED ON SOME UNITS).

NUMBERS 10 AND 11 ARE RELATED AND YOU NEED TO DECIDE WHETHER YOU
WANT TO HAVE TWO I/O CABLES PLUGGED IN AT THE SAME TIME SO YOU CAN
DETERMINE WHETHER YOU WANT TO DO 11 OR NOT.  THAT WILL DETERMINE
WHICH WAY YOU DO 10.  IF YOU HAVE TWO TERMINALS, ONE THAT USES RS232
AND THE OTHER THAT USES TTL, YOU MAY WANT TO BE ABLE TO SWITCH BACK
AND FORTH WITHOUT UNPLUGGING AND PLUGGING THE CABLE EACH TIME.  THAT
IS HOW BUTCH SWITCHES FROM THE APPLE TO THE COMMODORE.  I DO IT THE
OLD FASHIONED WAY BECAUSE MY OTHER TERMINAL IS STRICTLY FOR BACKUP
IN CASE THE COMMODORE GOES BELLY UP.
NOW, HOW TO DO THEM AND WHY.
1)  THE FILTER MOD CAN BE ORDERED (FREE FROM AEA).  THEY WILL SEND
YOU ALL OF THE PRECISION RESISTORS TO MODIFY THE FILTER FOR BETTER
RESPONSE.  IT WILL HAVE LESS RINGING AND A LITTLE MORE SQUARE
RESPONSE CURVE INSTEAD OF A PEAKED CURVE.
CONTINUED IN FILE AMT1.6