sun audio

[Don Duval]

In message <4421 at brazos.Rice.edu>, Doug Brooks states that:

>Of the 8-pin jack only 2 pins are used, pin 3 for the signal and pin 6 for
>the shield.
>
>The input is designed for direct connect via low impedance audio input as
>far as what I've been told.  I haven't yet tried it myself.  You could use
>a low -impedance microphone or you could use the output from a tape deck
>or CD player but those outputs are high impedance so you would need to
>feed them through a high-to-low impedance matching transformer first

Here is some better information on this topic. 

In the 4.0.3 Sun-4c Release Notes (800-4190-05) in the Devices and Network
Interfaces portion of Chapter 19, there is a description of the audio
device. Here is some additional information about the audio interface on
the SPARCStation1.

************************************************************************
Input:

The input is designed for microphone levels and not for line levels. The
input is designed for high impedance microphones. Devices such as tape
decks and CD players must have their signal level attenuated when using
them as sources for Campus audio files. Some local electronics stores
carry an attenuating adapter which has been used to digitize some source
material in engineering. (Radio Shack has a good selection of audio
adapters and has an attenuating adapter.)

***********************************************************************
Output:

The output jack on the rear of the Campus is designed to drive headphones
which have an impedance of 30 ohms (or higher) or powered loudspeakers.
Although the jack has two conductors in addition to the shield, the same
signal appears on both conductors. In other words, the output is not
stereo. 

***********************************************************************
I/O Connector:

This is the view looking at the connector end of an adapter cable. 

       6x  7x  8x
       3x  4x  5x 
         1x  2x

The connections to these pins are as follows: 

       Pin 1   no connect
       Pin 2   no connect
       Pin 3   audio in (tip)
       Pin 4   no connect>       Pin 5   no connect 
       Pin 6   audio in (sleeve or shield)
       Pin 7   audio out (tip)
       Pin 8   audio out (sleeve or shield) 

I hope this information helps those who wish to make use of the 
SPARCstation 1 audio feature.