Specifications

The table below shows the binary combinations possible, and what file they select:
8 4 2 1 File
Off Off Off Off None
Off Off Off On 1
Off Off On Off 2
Off Off On On 3
Off On Off Off 4
Off On Off On 5
Off On On Off 6
Off On On On 7
On Off Off Off 8
On Off Off On 9
On Off On Off 10
On Off On On 11
On On Off Off 12
On On Off On 13
On On On Off 14
On On On On 15
For example, connecting pins 8 and 27 together with the slide switch set in the
contact closure position will cause file 8 to run.
The loop input is read
at the end of the file.
The file will be looped if the loop command is asserted when the file ends. If the file
is a Play List, all tracks will be played and then the file will loop.
The file select inputs may also be strapped to automatically play a file on powerup.
That file number takes precedence over any autoexec files that may be on the internal
or removable drives (see power up operation). If an autoexec file exists and the loop
input is strapped, it will play indefinitely.
A file on the removable
media always takes
precedence over the
optional internal drive.
When using the file select inputs, files on the removable media take precedence over
those on the optional internal drive. In other words, the Digital Audio Machine looks
first at the PC-Card slot to see if it is installed. If it is, it looks for the file there. If the
PC-Card is not installed or the file doesn’t exist on it, then the Digital Audio
Machine looks for it on the internal drive. This allows files on the internal drive to be
temporarily replaced by simply plugging in a removable drive, a useful feature for
advertising insertion or special events.
The simplest possible configuration is therefore to connect four switches to the unit’s
four file select lines. These switches will play files 1, 2, 4 and 8. (The missing file
numbers need not exist.) Sixteen switches may be connected without an external
controller, by using a diode matrix. One side of each switch is connected to a wire
that goes to signal ground. The other sides of the switches are connected through
signal diodes, such as a 1N914 or 1N4148, to the file select inputs.