Controlling Virtual Channels - Polycom SoundStructure C16 Design Manual

When the logic output is set low (off), the transistor turns off and an open circuit is created between the logic
output and the chassis ground preventing any flow of current, as shown in the following figure.
Logic Output Pin Set to Low (Off)
Logic Output Pin
Logic Output = 1
High (On)
Chassis Ground
Examples of using logic input and output pins may be found in

Controlling Virtual Channels

The concept of virtual channels also applies to the logic inputs and outputs. The A/V designer can create
control virtual channels that consist of a logic input or output pin.
Logic pins can be defined via the command line interface from SoundStructure Studio or a control terminal
with the following syntax to define a logic input on logic input pin 1:
vcdef "Logic Input Example" control digital_gpio_in 1
which returns the acknowledgment
vcdef "Logic Input Example" control digital_gpio_in 1
A logic output pin definition using output pin 1 is created with the command:
vcdef "Logic Output Example" control digital_gpio_out 1
which returns the acknowledgment
vcdef "Logic Output Example" control digital_gpio_out 1
Once defined, the designer can refer to those control virtual channels by their name. As with the example
above, the designer created a control input virtual channel "Logic Input Example". The SoundStructure
device can be queried with a control system to determine the value of the logic pin and when it is active, it
could be used to change the status of the device. When the "Logic Input Example" input is inactive, it could,
for example, be used with an external control system to unmute the microphones. In version 1.0 of the
firmware logic pins must be queried by an external control system and then the control system can execute
commands or a series of commands on the device.
The value of control virtual channels may be queried by the control system by using the command
digital_gpio_state. An example of this is shown below.
get digital_gpio_state "Logic Input Example"
The state of digital logic output may also be set active using the digital_gpio_state command as
follows for the control virtual channel "Logic Output Example" that would be created with the vcdef
command.
Polycom, Inc.
Logic Output Pin
Logic Output = 0
Low (Off)
Chassis Ground
Using Events, Logic, and IR of this guide.
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