[net.micro.amiga] Amiga Sound INPUT ????

mjg@ecsvax.UUCP (Michael Gingell) (01/03/86)

While perusing the hardware manual and marvelling at the weird
things connected to pins on the Amiga Serial RS232 connector I
noticed the following:

Pin 15: Audio out of Amiga
Pin 16: Audio in to Amiga.

Question: Are these pins actually connected to anything, if so what?.
          Is the Audio out the sum of the two stereo channels or
          something else entirely.

As a side comment I find the Hardware manual sadly lacking in one major
respect - there are virtualy no diagrams. I got more understanding of
the structure of the Amiga and what is really going on from the Byte
article of last August. I know Commodore says they want to be open but
they have not given schematics or block diagrams. Admittedly there is
a lot in words but it is written as if they were trying to describe
the hardware to a blind man.

Mike Gingell     ...decvax!mcnc!ecsvax!mjg

sam@amiga.UUCP (Samuel C. Dicker) (01/07/86)

In article <1013@ecsvax.UUCP> mjg@ecsvax.UUCP (Michael Gingell) writes:

>While perusing the hardware manual and marvelling at the weird
>things connected to pins on the Amiga Serial RS232 connector I
>noticed the following:
>
>Pin 15: Audio out of Amiga
>Pin 16: Audio in to Amiga.
>
>Question: Are these pins actually connected to anything, if so what?.
>          Is the Audio out the sum of the two stereo channels or
>          something else entirely.

The audio out on the serial connector has the same signal as the left stereo
output jack (the sum of audio channels 0 and 3).  It is on the serial port
to allow a telephone answering device to speak and play music over the phone
line.

The audio in is mixed with the right stereo channel from the Amiga (the sum
of audio channels 1 and 2) and connected to the right stereo output jack.
It allows you to monitor the output of a telephone answering device on your
stereo or the little speaker in your video monitor (YUK!, the Amiga should
only be connected to your stereo :-) ).

The audio in does no signal processing (such as analog to digital conversion)
other than passing the signal through the anti-aliasing filter (don't ask me
why?).  I hope that no one was misled by the term 'audio in'.

		Sam Dicker (...!decvax!decwrl!pyramid!amiga!sam)