Composite BNC Connections
These are usable only if your VOLT is running the FM or SG (Stereo Generator) DSP|Cores.
Composite Outputs
These are two BNC outputs, to feed VOLT’s multiplex signal to your transmitter(s). Each is
separately adjustable from 0 V to 10 V p-p in .05v steps. Pre-emphasis curve and mode, pilot
level and phase, and stereo separation are also adjustable. See the chapters on Front Panel opera-
tion or Remote Control for details.
SCA Input and Gain
This BNC input can be used for Subsidiary Communications (SCA) such as reading for the
blind or data casting. A signal from an external SCA or RDS generator, at this input, is mixed
into both composite outputs.
The Gain trimmer lets you adjust between -29 dB and +2.6 dB, accommodating signals between
10V and .25 V p-p for 8.6% injection on a 3.6 V composite output.
19k Sync Out
This is a TTL-level 19 kHz square wave, locked to VOLT’s stereo pilot, for use as a reference for
most RDS or SCA generators that operate at multiples of the 19 kHz pilot frequency.
Data Connectors
Serial I/O
This is a DB9-M for factory maintenance; it is not used in normal VOLT operation.
GPI
This is a DB9-F for remote control input, using contact closures or other logic-level systems.
Pin 1 +5VDC Out
Pin 2 Input Common +
Pin 3-6 Trigger input #1 - #4
Pin 7,8,9 GND
The action for each input is controlled by the GPIO/Events tab in the Remote Control.
If using pushbuttons or relays, each GPI activates by momentarily connecting its Trigger input
to Ground, while pin 1 is tied to pin 2. (For noise immunity, you may wish to pull the input line
“normal high” by connecting it to the +5V supply through a 1kΩ resistor.)
CHAPTER 3
| 15
INSTALLATION AND REAR PANEL
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