Cessna 172S Pilot Operating Handbook page 232

S ECTION 9 S U PPLEM ENTS
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S U PPLEMENT 25 - FAA APPROVED
1 2. COMM F REQUE N CY TRAN S F E R B UTTON
I nterchanges the frequ encies
displays. To tune the rad io to the desired operating frequency,
the desired frequency m u st be entered i nto the standby
display and then the COMM TRAN S F E R button m u st be
pushed. This will trade the contents of the active and sta ndby
displays . The operating freq uency can a lso be entered by
accessing the ACTIVE E NTRY (direct tu ne) mode which is
done by p ushing the COMM TRANS F E R b utton for 2 or more
seconds. In the direct tune m ode, only the - active part of the
d isplay is visible. The desired frequency can be directly
entered i nto the display. Push the COMM TRAN S F E R button
again to return to the active/standby display.
The transceiver is always tuned to the frequency a ppearing in
the ACTIVE display. It is, therefore, p ossible to h ave two
different freq uencies stored in the ACTIVE and STA N DBY
displays and to change back and forth between them at the
simple push of the COMM TRANS F E R b utton.
1 3. COMM VOLUM E CONTROL (OFF/PULLITEST) -- Rotate the
VO L knob clockwise from the OFF position. Pull the VOL knob
out and adjust for desired l istening level . Push the VOL knob
back in to actuate the automatic squelch . The VOL knob m ay
also be pul led out to hear parti cularly weak signals.
There i s no change t o t h e airplane l i m itations when t h i s avionic
equipment is installed .
S25 - 1 0
in the
S ECTI O N 2
L I M ITAT I O N S
C E S S NA
M O D E L 1 72S
U S E and STAN DBY
Jan 3 1 /02