Chapter 2 NISPEEDY-33 Functional Description and Interface
NI SPEEDY-33 User Manual 2-10 ni.com
Jumpers

Audio Input Level Jumpers

The audio input level jumpers (J1, J2) control the amount of gain applied
to the input audio signals.
The microphone level setting has the highest gain for the onboard
microphones (U2, U5), the line level setting has less gain and is appropriate
for the line level audio interface (for example, CD players, MP3players,
and so on).
These settings will affect the gain of the external audio source and should
be left in the line level setting if an external microphone or audio source
is used at audio stereo input port (U10), described in the Stereo A/D, D/A
(Analog Input, Analog Output) section. Table2-2 shows the possible audio
input level settings.
Caution Ensure that line level audio signals are not connected to the audio input when the
NISPEEDY-33 is configured in the microphone level setting. It is possible to damage the
audio input circuitry by overdriving the input.
Table 2-2. Audio Input Level Jumpers (J1, J2) Settings
Jumper
Microphone Level
(DefaultSetting) Line Level
Audio Input Level,
Left Channel (J1)
Position 1 Position 3
Audio Input Level,
Right Channel (J2)
Position 1 Position 3
123 123
123 123