Garmin SL10 - Manual (Page 12)

UPS Aviation Technologies
SL10 Series Audio Selector Panel and Intercom System
User’s Guide
Page 8
The same pins are used for both mono and stereo SL10 Systems. This
applies ONLY to units with applicable serial numbers.
1.6 Marker Beacon (SL10M, SL10M-S
The optional Marker Beacon Receiver uses visual and audio indicators to
alert you when the aircraft passes over a 75 MHz transmitter.
The Blue lamp, labeled "O," is the Outer Marker lamp and has an
associated 400 Hertz 'dash' tone. The lamp and tone will be keyed at a
rate of two tones/flashes per second when the aircraft is in the range of
the Outer Marker Beacon.
The Amber lamp, labeled "M," is the Middle Marker lamp and is coupled
with a 1300 Hertz tone. It is keyed alternately with short 'dot' and long
'dash' bursts at 95 combinations per minute.
The White lamp, labeled "A," is the Airway/Inner marker and has a 3000
Hertz 'dot' tone. The lamp and tone will be keyed at a rate of six times
per second.
The audio from the Marker Beacon Receiver can be heard by selecting
the "M" push-button switch. To adjust the volume level, there is a service
adjustment located on the top of the unit. See Section 2.5
A 3-position switch is used to set the receiver sensitivity and to test the
indicator lamps. Use "H
IGH " sensitivity initially. This allows you to hear
the outer marker beacon about a mile out. Then select the “L OW ”
sensitivity to give you a more accurate location of the Outer Marker. The
momentary down switch position is labeled "T
EST " and illuminates all
three lamps simultaneously to assure the lamps are in working order.
Upon first application of power to the unit, the Marker enters a self test
mode. The flickering blue marker light indicates a test in process. If the
test continues for more than 10 seconds, or the lamps do not extinguish,
return the unit for service.
1.6.1 Middle Marker Sense
A Middle Marker sense output signal is available to automatically reduce
the autopilot sensitivity after the aircraft has passed over the Middle
Marker. This function will not operate during the test mode. This output
will go to +4.75 VDC (
± 0.25 VDC) when a valid Middle Marker signal
is received.
1.6.2 External Marker Lights (SL10, SL10S)
For installations that require external marker beacon lights, there are
three outputs that can drive 12 Volt lamps only. The external output
lamps are driven high (+9 VDC
±0.5 VDC) when active. Maximum
source current per lamp is 125 mA.