Section II. OPERATION - TM-11-5831-201-200016

11-5831-201-20

Section II. OPERATION

talking. Talk in both directions to check the pri-

2-2. Modes of Operation

vate interphone line,

a. Three modes of operation (receiver moni-

toring, two-way voice radio, and intercommuni-

NOTE

cation over the common interphone line) may be

If the MD736/A is installed in the air-

used between all C1611D/AIC control sets. In

craft, observe the preflight check pro-

addition, a fourth mode of operation (private in-

cedures in chapter 4.

terphone) may be used between any two equip-

ments specifically wired for this type of opera-

2-4. Operating Procedures

tion.

a. Starting. Turn on the power system for the

b. Any mode may be selected by a crewmember

aircraft navigation, communications, and inter-

having access to all these facilities. In some in-

phone systems and check to see that the headset-

stances, only the receiver monitoring and inter-

microphone plug (fig. 13) is inserted in the

phone communication modes are available at a

headset-microphone output jack. No other start-

particular control set. It is important to deter-

ing procedures are required.

mine which modes of operation are available be-

b. Two- Way Radio Communication. Two-way

fore attempting to operate the control unit. This

radio communication through a C1611/AIC sys-

should be done during preflight checks before the

tem is available to the pilot, copilot, and, in some

aircraft leaves the ground (para 23).

installations, to a third crewmember. To use the

c. To operate the equipment or any particular

C1611D/AIC in conjunction with the two-way

mode of operation, perform the following pro-

radio, proceed as follows:

cedures:

(1) Operate the transmit-interphone selec-

tor switch to the desired transmitter position (1,

(1) Preflight checks (para 2-3).

2, 3, or 4).

(2) Starting procedure (para 2-4a).

(2) Operate the transmit-interphone talk

(3) Procedure for the desired mode of oper-

switch to the transmit position and speak into

ation (para 24).

the microphone.

(4) Stopping procedure (para 2-4.f).

(3) Adjust the volume of received signal to

a comfortable level with the VOL control.

2-3. Preflight Checks

a. Start the system (para 24a). Check each

NOTE

associated radio transmitter, one at a time, by

When the transmit-interphone selector

depressing the transmit-interphone talk switch

switch is operated to position 1, 2, 3,

(external control) to the transmit position and

or 4, it connects the associated radio

operating the transmit-interphone selector switch

receiver to the headset-microphone as

on the control set sequentially to positions I, 2, 3,

well as the transmitter. Therefore, it

and 4 and listening for sidetone. (Some user's

is necessary to operate a RECEIVERS

stations, other than the pilot's or copilot's station,

1, 2, 3, or 4 switch, except when moni-

may not have access to transmitter. )

turinx more than one radio receiver.

b. Operate RECEIVERS NAV switch to ON

(Interphone

Line).

c..Intercommuncation

and listen for receiver noise to check vhf naviga-

Three methods of operation are possible. The

tion, low frequency navigation, and marker bea-

method selected by each crewmember depends on

con radio receivers.

the switches available at the interphone station.

c. Call each user's interphone station one at a

(1) Tranmitter-interphone talk switch (er-

time and ask for a reply (para 24c) to check the

tcmal control). Select one of the two following

intercommunication system, Listen for sidetone

methods:

while talking.

(a.) Operate the transmit-interphone talk

d. When the equipments wired for the private

switch to the interphone position and speak into

interphone feature are used, operate the transmit-

the microphone.

interphone selector switch to PVT and call the

other connected station wired for PVT mode

(b) Operate the transmit-interphone se-

(para 2-4e). Sidetone should be heard while

lector switch on the control set to the INT posi-

2-2