Installation manual

UPS Aviation Technologies
SL10 Series Audio Selector Panel and Intercom System
Installation Manual
2-5
located at the lower right hand side of the unit face will automatically adjust the backlight of the push-
button lamps as well as the rotary mic selector switch light intensity.
2.4.9 Speaker Loads
Certain VHF Nav/Comms, such as King KX170-series have internal speaker amplifiers. These are not used
with a SL10, but must be loaded to prevent unit failure. Connect the speaker output from the Nav/Com to
the appropriate load on the SL10 (bottom connector 19 and L for COM 1, etc).
2.4.10 PA Mute
Bottom connector pin 18 is a TTL logic output that is pulled low during PTT operation. This serves as an
input to external public address system to prevent feedback during transmissions.
2.4.11 Middle Marker Sense
The MM Sense output is connected to specific autopilots, and goes high only when a middle marker signal
is received, not in test.
2.4.12 Unswitched Inputs
The SL10 has two unswitched inputs. Bottom connector pin 17 is unswitched, but muted by transmissions.
This signal can be used for less critical inputs such as airborne telephone ringer.
Bottom connector pin T is an unswitched and unmuted audio input. This audio is always presented to the
headphones and speaker, regardless of the audio panel audio selections. This input can be use for critical
warnings, such as radio altimeter warnings.
2.4.13 Intercom
The top connector is for the intercom function. All mic and headphone jacks must have insulating washers,
the cable must be Teflon coated, twisted-shielded wire, and the shield must only be connected to the ground
return wire only at the intercom connector. NOTE: This harness can be custom made by UPS Aviation
Technologies, Inc. Simply call the factory and obtain a wire harness work-sheet. The harness will be made
to your specifications and fully functionally tested. All hardware is included. (See Appendix C (mono) and
E (stereo) for intercom connection configurations).
2.4.13.1 Push-to-talk intercom
SL10-series units with intercom board (second series of numbers on data plate) serial number above a “G”
series in stereo, or “MO series in mono, include a push-to-talk intercom capability.
In some extremely high noise environments, it may be desirable to have a push to talk (PTT) intercom,
instead of relying on voice-activation (VOX).
To operate the PTT, simply rotate the SL10 squelch control to maximum (fully CW). Grounding the
appropriate pin on the top connector through a momentary switch will open only that intercom channel.
The pilot and copilot are individually controlled (Top connector, pins 22 and 21, respectively). All
passenger mics are controlled with pin 20.
The same pins are used for both mono and stereo SL10 Systems.
This applies ONLY to units with applicable serial numbers. If a unit with serial number below that
indicated is installed in a position wired for the PTT, no damage will occur, only the ICS PTT function will
not function.
2.5 Adjustments
The SL10 is factory adjusted to accommodate the typical requirements for most aircraft configurations.
There are three adjustments however, that will allow the installer to tailor the specific functions. The
numbers correspond to identification numbers stamped on some trays.