How does the tapedrive work ? doers it have the D/A converter inbuilt
or is this handled by the computer ?

I have the pinconfig of the connector, and it contains

1 - +12v
2 - CASR
3 - CASW
4 - AUDIO
5 - GROUND
6 - ME
7 - READY


CASR and CASW is "Casette Read" and "Casette Write", should I take that as it is
digital data ? or is it analog ? or is it just signals that gos high when the computer
is sending or reciving data ? ..Or is the real datachannel the AUDIO pin ?

..And what is ME ?

The CASR and CASW signals are digital data and TTL level for reading and writing to cassette. The data is stored in a custom FSK modulation.

And the /ME (Motor Enable) is a control signal to the cassette recorder to turn the motor on and off. This signal is written to using the 8255 PPI port C and is named /CASON.

There is also a feedback signal from the cassette recorder to check if the motor is running. This signal is called /READY and is read using the 8255 PPI port A.

PPI Port A Input (address 98H)
Bit Name Description
0 TA Joystick 1, /SENSE
1 TB Joystick 1, EOC
2 TC Joystick 2, /SENSE
3 TD Joystick 2, EOC
4 TRIGGER1 Joystick 1, Trigger
5 TRIGGER2 Joystick 2, Trigger
6 /READY Cassette, Ready
7 CASR Cassette, Read data

PPI Port B Input (address 99H)
Bit Name Description
0 IN0 Keyboard, Column status of selected line
1 IN1 Keyboard, Column status of selected line
2 IN2 Keyboard, Column status of selected line
3 IN3 Keyboard, Column status of selected line
4 IN4 Keyboard, Column status of selected line
5 IN5 Keyboard, Column status of selected line
6 IN6 Keyboard, Column status of selected line
7 IN7 Keyboard, Column status of selected line

PPI Port C Output (address 96H)
Bit Name Description
0 KB0 Keyboard, Line select 0
1 KB1 Keyboard, Line select 1
2 KB2 Keyboard, Line select 2
3 KB3 Keyboard, Line select 3
4 /CASON Cassette, Motor relay control (0=on, 1=off)
5 CASW Cassette, Write data
6 CASAUD Cassette, Audio out (pulse)
7 SOUND Keyboard, Click sound bit (pulse)

PPI Mode Control Output (address 97H)

Port C Status Input - low nibble (address 9AH)

Great, this will help me :)

But how about the AUDIO pin ? what is it used for ?