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5.3 Audio Bypass
In safety critical applications, a bypass system should be included to maintain communications in the
unlikely event of the
NEDSP1901 or power
failing. The following circuit
uses a relay to route the
audio signal directly. In the
event that the power fails,
the Relay will de-energise
and connect the Input to
the Output directly. It will
be noted that a switch has
been included to allow the
signal to bypass the
Module.
Fig 12. Typical Relay operated audio bypass circuit with user Power Off/Bypass switch
