Audio Connections - Bose ControlSpace Safety Instructions & Install Manual

Audio connections

A microphone or line level audio source can be con-
nected to the Mic/Line inputs using one of the following
wiring methods.
General Purpose Inputs/Outputs (GPIO)
cards
Two GPIO card slots provide up to 16 control inputs
and 16 control outputs. The GPIO inputs are used to
accept hardware-based control signals from switches,
relays or potentiometers.
Inputs
Switches and potentiometers can be connected to
the control inputs to control various functions in the
system. For example, simple ON/OFF switches can be
connected and then programmed to invoke presets,
select scenes, or invoke a snapshot of a control. Like-
wise, 10k potentiometers (linear) can be connected to
control gains in the system.
When used for gain control, the control input expects
to see 0 ohms for full gain and 10k ohms for "OFF" or
muted. This is to prevent unterminated or loose con-
nections from inadvertantly causing full-gain audio,
since the port features an internal pull-up resistor.
Therefore, wire the potentiometer such that the fully
rotated clockwise position (full gain from the user's
perpective) is 0 ohms and the fully counterclockwise
position is 10k ohms.
Modularity and Expansion
7
Inputs include a 5k ohm pull-up resistor allowing SPST
switches to be wired from input to ground. Potentiom-
eters can be wired in series from the control input to
ground.
Outputs
LEDs and relays can be connected to general purpose
outputs to indicate state changes in the system (e.g.
preset or scene changes).
A maximum of 10mA (sink; 0.5mA source) per output
is available and therefore care must be taken when
selecting components. Select LEDs that are "High
Efficiency" and require only 10mA forward current. For
relays, only those rated with an LED forward current
of 10mA or less, such as some solid state relays, can
be connected directly. Most mechanical relays require
more than 10mA drive current and are not suitable for
direct connection. Alternatively, an external power sup-
ply and transistors can be used to drive higher current
LEDs or relays.