ARA-1 Operations Manual
INTEROPERABILITY NOW
2-7
Table 2-2
ARA-1 Pinout (J7)
PIN
Signal
Description
1
Ground
Ground connection
2
N/A
Not used
3
/AUX In 0
Auxiliary Input 0 - Active low
4
/AUX Out 0
Auxiliary Output 0 - Active low
5
Ground
Ground connection
6
Audio Input
Balanced audio input
7
Analog Ground
Analog ground
8
Audio Output
Unbalanced Audio output
9
N/A
Not used
10
/AUX In 1
Auxiliary Input 1 - Active low; general purpose
11
/AUX Out 1
Auxiliary Output 1 - Active low; general purpose
12
/COR Input
Input from radio COR, programmable active high or low
13
/PTT Out
Output to radio PTT, active low, open drain
14
Audio Input
Balanced audio input
15
Analog Ground
Analog ground
NOTE:
To interface unbalanced “single-ended” audio, connect the audio to one of
the two balanced audio inputs and ground the other. Interface cables purchased
from JPS handle the unbalanced/balanced audio issue properly.
2.8.3
Audio Level Adjustment Potentiometers and Input Test Point
The audio input level to the ARA-1 is set by adjusting the IN LVL control on the rear panel. With
“normal radio receive audio” input applied at J7, adjust the IN LVL control until the AUDIO
INPUT indicator flashes on voice peaks.
NOTE:
“Normal radio receive audio” means the audio output that results when
receiving a fully-quieted (on frequency) speech signal from someone talking at a
typical speaking volume.
The OUT LVL control sets the audio output level from the ARA-1 and may be adjusted to the
level suitable for the equipment connected to the unit. If necessary, the input audio level can be
further boosted within the unit’s software (see Section 3.3.6).
A test probe may be inserted into the test point to measure the level of the incoming audio. The
proper audio input level may also be set by connecting an AC voltmeter to the test point TP1 on
the real panel and adjusting the IN LVL control for an average audio level of about 0.2V or –
12dBm.