ACCESS/A A711 L-Series Installation & Operating Instructions 09RE416
Technisonic Industries ltd. Copyright 1996, 1997, 2010, 2011 BY TiL ALL RIGHTS RESERVED Page 2-20
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Figure 2-13 Full A711L Connector Map (view from mating connector wiring side)
2.7
HEADPHONE
INSTALLATION
The A711L ACCESS/A Audio Controls are intended for use with industry standard 150/600 ohm
headphones. There is also provision for connection to an 8 ohm (minimum impedance) speaker, for
a supplemental cabin speaker output. The pilot’s headset (only) may also be strapped internally for
a standard low impedance headset (8-20 ohms) at the same power level.
In all cases, the headset lines should be run as shielded, twisted pairs, to avoid contamination (and
resulting cross-talk) of companion low level mic lines or audio input lines. Failure to follow this wiring
guideline will result in unwanted cross-talk, and phantom audio that will appear to be transmit or
intercom related.
The use of high quality headsets and “carbon-equivalent” boom microphones, such as David Clark
or Bose is strongly recommended. Mixed headset impedances within the same ship will give
differing volume levels at the same A711L control settings. The use of headsets with individual
volume controls is very useful for passengers to permit level adjustment suitable to each
position, due to differing headsets and the inevitable different hearing capability of individual users.
