(2)  
The airplane shall be located with respect to the ground station such that there are no buildings or other obstacles in the transmission path between ground station and airplane.

B.  Equipment Required
(1)  
Selcal Ground Station Encoder - Motorola N-1001A/NA128 (rack-mounted) or N-1000A/NA127 (Console)

(2)  
VHF transmitter

(3)  
HF transmitter

C.  Prepare to Test
(1)  
Connect external power to the airplane.

(2)  
Ensure power is available to load control centers P6 and P18, and both master radio switches are closed.

(3)  
Ensure Selcal, Interphone, HF and VHF circuit breakers are closed.

(4)  
Turn on HF and VHF systems and confirm all systems are operable.

(5)  
Make arrangements for ground operator to transmit selected code signals as necessary. Transmissions shall be made only on authorized frequencies.

D.  Test Selcal System (GJ B-2501 thru B-2503 and B-2509 thru B-2510 and B-2524)
(1)  
Select an authorized test frequency on VHF-1 control panel.

(2)  
Contact ground station and have operator transmit code signal on the desired test frequency.

NOTE:  Airplane selcal code is marked on a placard located on the main instrument panel. Voice communication shall not be made during code transmissions.
(a)  
The selcal No. 1 light should illuminate.

(b)  
The chime shall emit a repetitive tone.

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(3)  
Press the RESET button on the control panel. The light should go out and the chimes stop.

(4)  
Repeat steps D.(1) thru D.(3) using HF-1 system. Results should be similar.

(5)  
Repeat steps D.(1) thru D.(3) using VHF-2 system. Results should be similar except that selcal No. 2 light should come on.

(6)  
Repeat steps D.(1) thru D.(3) using HF-2 system. Results should be similar except that selcal No. 2 light should come on.

(7)  
Secure HF and VHF systems.

(8)  
Determine whether there is any further need for electrical power on the airplane; if not, remove external power.

E.  Test Selcal System (GJ ALL EXCEPT B-2501 thru B-2503, B-2509 thru B-2510 and B-2524)
(1)  
Select on authorized test frequency on VHF-1 control panel.

(2)  
Select VHF-1 on SELCAL-1 and SELCAL-2 selector switch.

(3)  
Contact ground station and have operator transmit code signal on the desired test frequency.

NOTE:  Airplane selcal code is marked on a placard located on the main instrument panel. Voice communication shall not be made during code transmissions.
(a)  
Verify selcal No. 1 and No. 2 illuminates.

(b)  
Verify repetitive tone from the aural warning unit.

(4)  
Press the selcal reset buttons and verify the lights go out and tone stops.

(5)  
Repeat steps E.(1) thru E.(4) using VHF-2 system. Results should be similar.

(6)  
Repeat steps E.(1) thru E.(4) using HF-1 system. Results should be similar.

(7)  
Repeat steps E.(1) thru E.(4) using HF-2 system. Results should be similar.

(8)  
Secure HF and VHF systems.

(9)  
Determine whether there is any further need for electrical power on the airplane; if not, remove external power.

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PASSENGER ADDRESS SYSTEM - DESCRIPTION AND OPERATION
1. General (Fig. 1)
A.  The passenger address (PA) system provides means of communicating with the passengers and entertaining them with recorded music played over the speakers in the passenger compartment. It also provides chime signals for the Passenger Call Systems (Ref Chapter 33), Flight Crew Call System (Ref 23-43-0), and Passenger Signs (Ref Chapter 33) to attract the attention of flight attendants as well as passengers. Announcements may be made using any of the three hand microphones or using the microphones and audio selector panels in the flight interphone system.
B.  The passenger address system consists of a PA amplifier, loudspeakers, microphones, a tape reproducer, and interconnecting wiring.
C.  Power for the system is 28 volts dc and 115 volts ac provided through circuit breakers on the P6 panel.
2.  Passenger Address Amplifier
A.  The passenger address amplifier provides high-quality audio power to the speaker system of the airplane. It includes microphone inputs for use by the pilot and cabin attendants and two balanced inputs for use with tape reproducers for announcements and programmed music. The amplifier has high, high/low, and low chimes for use by the pilot and passengers.
　
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