ADAM Auto-Answer Interface for ADAMLink modems
by Ronald McDonald and enhanced by Shawn Merrick

                       C1
              I--------)(---------I
              I                   I
I-------I     I                   I
I       I     I    [Relay Coil]   I
I B    +I-----I------->coil<------I---------I
I r     I                                   I
I i     I                                   I
I d     I       C2                          I
I g R  ~I-------)(-----------[Tel.Line]     I
I e e   I                                   I
I   c   I                                   I
I   t   I                                   I
I   i  ~I--------------------[Tel.Line]     I
I   f   I                                   I
I   i   I                                   I
I   e   I        R1                         I
I   r  -I------\/\/\/-----------------------I
I       I                                    
I-------I                                    

(Note:  Wire colors below are those from a standard Coleco
Vision joystick controller.  If you have a spare one, it's
the best source for the cable for PORT 1)

(Submini Switch)       (relay       [D1]
[to middle pole]<------->SPST<-----(I   )----->[to pin 6]
                       contacts)               (blue wire)

[Left pole = Pin 8 (gray)]
[Right pole = Pin 5 (green)]

(Note:  To complete the diagram, use a ruler and felt tip
pen to make solid lines on the dash lines and I's.
PORT 1 is numbered as below.)

                        PORT 1
                    (looking at rt.

                   \  1 2 3 4 5  /
                    \ . . . . . /
                     \ . . . . /
                      \6 7 8 9/

                   side of console)

                    An Explanation

    Only when the phone line rings, an AC voltage is passed
through C2, rectified by the bridge and appears as DC at the
+ and - leads. This DC voltage is then reduced to about 8-12
volts by R1 then applied to the coil which causes the relay
contacts to close. This simulates a joystick trigger being
pushed. For convenience Radio Shack #'s are listed below:
(The "=>" indicates modifications by Shawn Merrick)

    R1- 5.6K ohm 1/2-watt resistor...271-031    Pk 2 =  .19
=>  C1- 2.2 uf  Capacitor............272-1435   Pk 1 =  .69
    C2- 4.7 uf  Capacitor............272-1012   Pk 1 =  .49
    Relay- 12 Volt Reed Relay........275-233    Pk 1 = 1.89
    Bridge Rectifier.................276-1152   Pk 1 = 1.19
    D1- 1N914/1N4148 Diode...........276-1122   Pk 10=  .99
=>  Switch- Submini DPDT.............275-407    Pk 2 =  .89
=>  Phone cord- 12" Mod-to-spade.....279-391    Pk 1 = 1.99
=>  Plastic Casing w/ IC board.......270-283    Pk 1 = 3.99

OPTIONAL 10' JOYSTICK extension cable may be used in place
of Coleco controller, but color codes will NOT be the same,
and may not even match from one 10' cable to another!  This
is part # 270-1705 priced $5.49

The values above are the ones that worked best for me and
should work well on all standard phone lines.  Using the
relay, ADAM isn't directly connected to the phone line and
is "safe".  Looking at the diagram the connections marked
[Tel.Line] are the ones to be connected to the red and green
wires from your phone line.  With modular phone jacks these
are the two center contacts. (Polarity doesn`t matter.)

Note:  I have found that polarity MAY affect the sensitivity
of the circuit.  If you find the device does not work very
smoothly, try reversing the connection where the phone line
enters the circuit.  -Shawn

C2 belongs inline with either of the leads from the bridge
rectifier marked ~ (or AC). The + side of the bridge goes to
one side of the relay coil (see back of package), and to one
side of C1. The other side of the coil and C1 then go to one
side of R1. The other side of R1 then goes to the - of the
bridge rectifier. On to the joystick connection...
The only critical thing here is the polarity of the diode
(D1). Looking at the diode you will see a band toward one
end (I tried to show it in the diagram), the opposite end
(no band) MUST be connected to pin 6 (blue wire). From there
the end with the band goes to one of the relay's switch
contacts, and on to the middle pole of the DPDT switch.
Place Pin 5 (green) on the RIGHT pole and Pin 8 (gray) on
the LEFT pole of the switch.  This allows you to simulate
either a LEFT button or RIGHT button, depending on the
position your switch is in.

    It's a good idea to check out the circuit before you
plug into PORT 1. With the phone line connected and ringing,
stick the + lead of an ohm meter into pin 6 and the - lead
into pin 5 (or 8) at the end of the j-stick cable and check
continuity. You should see the meter going on and off. If
not check that D1 is correct! Then check for 8-12 volts
across the relay coil going on and off. If necessary try
changing the value of R1 by about 1000 ohms at a time.

           Program Line Changes for the Mini-BBS
    The following changes will make the program respond
to the #1 joystick right TRIGGER button, or the interface:

160 PRINT:PRINT:PRINT"Hit <Right TRIGGER> to answer"
170 IF PDL(9) <> 1 THEN 170: REM check right trigger
180  (line 180 deleted)

Leave EZ if you have any problems or questions.
Ronald McDonald, 75766,42
Shawn Merrick 73307,3262
