— 5 —
ground for an alarm condition. Up to
100mA may be ‘sunk’ by each of these
outputs to operate relays or LED indica-
tors using an external voltage source up
to 24VDC, which must be returned to
the
G
(Ground) terminal. The +9VDC
supplied on the
+9
terminal is current-
limited with a 300-ohm series resistor
and suitable only for optical couplers,
LED indicators or small reed relays.
The plastic connector body may be un-
plugged from the chassis to make con-
nection easier and for quick disconnect.
ANALOG LINE
OUTPUTS L/R
The active-balanced analog line outputs
provide a program level of +4dBu for a
front-panel meter indication of
0dB
.
These outputs have a 200-ohm source
impedance.
AES DIGITAL
AUDIO OUTPUT
The balanced, transformer-isolated AES
digital audio output has a fixed sam-
pling rate of 44.1kHz. The level is
–6dBFS for a front-panel meter indica-
tion of 0dB
+12VDC
POWER I/O
These two parallel connecters allow
‘daisy-chaining’ INOmini modules. A
single DC supply may power up to
three modules mounted in a single rack
adapter, provided that the rating of the
supply is not exceeded. Two short ‘pig-
tail’ cables are provided with each rack
adapter.
The Model 514 decoder draws 230mA.
Check the rating on the label of the
power supply to make sure of the ca-
pacity for the modules it must support.
These power connectors are not a lock-
ing type, and the mating plugs pull out
rather easily. A Ty-Wrap® will secure
the cables to the plastic anchor above
the jacks if this might be an issue.
— 6 —
Section III
OPERATING THE 514 DECODER
Program Audio De-Emphasis
FM-stereo broadcasting utilizes complementary pre-empha-
sis (transmission) and de-emphasis (reception) to improve
the perceived signal-to-noise ratio. The Western Hemi-
sphere employs a 75-microsecond (75µs) characteristic, and
the rest of the world a 50µs one.
The INOmini 514 accommodates either de-emphasis stand-
ard, and is shipped from the factory with the destination-
applicable characteristic enabled. This is easily changed (or
confirmed) in the field, however, by removing the top cover
of the unit. Simply unscrew the one flathead screw on top
and pull the cover off.
A pair of push-on jumpers will be found just beside the
MPX INPUT LEVEL SET
control, as shown in the two snap-
shots below. The illustrations show the proper setting of
these jumpers for 75µs and 50µs de-emphasis settings.
75µs
(Jumpers to the Right)
50µs
(Jumpers to the Left)
The Front-Panel Meters
The two LED meters indicate the peak level of the decoded
left and right program audio channels. These meters will,
of course, follow the selected de-emphasis characteristic.
This means that the meters will indicate a progressive roll-
off of the higher audio frequencies. Thus for level-setting
