Compact FLASH III Digital Audio System
Copyright©1992-2010 by ACS, Sarasota, Florida
6
ALL RIGHTS RESERVED
are buffered by an inverting gate. The following diagram is representative of the Contact #25 input and is
similar for Contact #26:
Contact #25
GROUND
+12v
+5v
680
ohm
10K
ohm
The input is activated by sinking current from the Contact input pin to ground. A Ground connection is
supplied on pin 10 of the
Main
connector for this purpose. The input current sink requirement is
approximately 10mA. The contacts are associated with sound files named 19x.WAV and 1Ax.WAV. The x
denotes additional file control attribute characters. See the
Filename Formats
section below.
Speaker Connection
The speaker terminals on the
Main
connector provide connections for the two external left and right
speakers. These may be either 4 or 8 ohm speakers, with 4 ohms providing higher output power. The speakers
should be capable of handling up to 25 watts.
NOTE: THE SPEAKER OUTPUTS ARE NOT REFERENCED TO GROUND – EACH
SPEAKER REQUIRES ITS OWN PAIR OF WIRES, AND NEITHER WIRE MAY BE
CONNECTED TO GROUND.
G
R
O
U
N
D
1
0
V
-
1
8
V
D
C
P
T
T
C
o
n
ta
c
t N
.O
.
P
T
T
C
o
n
ta
c
t C
O
M
In
p
u
t C
o
n
ta
c
t 2
6
In
p
u
t C
o
n
ta
c
t 2
5
R
ig
h
t S
p
e
a
k
e
r +
L
e
ft
S
p
e
a
k
e
r -
L
e
ft
S
p
e
a
k
e
r +
R
ig
h
t S
p
e
a
k
e
r -
1
2
3
4
5
6
7
8
9
10
Pin #
Signal
Filename
1
Left S
2
Left Speaker -
3
Right S
4
Right Speaker -
5
Input Contact 25
19C.WAV / 19O.WAV
6
Input Contact 26
1AC.WAV / 1AO.WAV
7
PTT Contact COM
8
PTT Contact N.O.
9
10VDC – 18VDC
10
Ground
Serial Connector
A standard RS-232 serial interface is provided on-board via a DB-9 style male connector. The CFSound-
III provides diagnostic messages about CF card insertion and removal events and sound contents over the
serial port. Additionally, the playing of sounds may be controlled by messages issued to the CFSound-III via
the serial port. The format of the serial data is 2400 baud, 8 data bits, 1 stop bit and no flow control, and the
baud rate may be changed using a configuration file entry or NVM setting. Only three of the nine pins are
used. The configuration of jumper block JB2 on the CFSound-III controls whether the serial port looks like a
