MAJOR COMPONENTS

INTERCOMMUNICATION SYSTEM (ICS) Learning Objective: Recognize components and operating features of an inter- communication system used in naval aircraft. The intercommunication system that will be discussed in this section is the OK-248( )(V)/AI, Intercommunication-Communication Control Group (ICCG). This system is found on the S-3 aircraft. The OK-248( )(V)/AI provides intercommuni- cations for crew members and maintenance personnel. It also controls operation and signal interfacing for all radio sets, and controls operation and signal interfacing for aural monitoring of the navigation aids. MAJOR COMPONENTS The following is a discussion on the various com- ponents in the OK-248( )/AI system. C-8760/AI Intercommunication- Communication Control Panel The C-8760/AI (fig. 1-1) is commonly called the integrated radio control (IRC). The IRC panel performs the following functions: Controls HF radio modes and functions Controls UHF radio modes and functions Displays In-Flight Performance Monitor (IFPM) status of communication subsystems and components Initiates on-line operating configuration of communication systems There are eight switches for the HF system function selections, along with a squelch knob. These switches are used to select the various modes of operation for the HF system on board. The squelch knob is turned clockwise to increase squelch and counterclockwise to decrease squelch. The next section of switches (labeled UHF) on the IRC panel are used to control the UHF radios. There are twelve of these switches but only eleven are used. The switch labeled SPARE is not used. The next section consists of a numerical keyboard, five switches, and three sets of indicators. The keyboard is where the operator inputs the desired channel and frequencies for the HF and UHF radios. The CLR button Figure 1-1.-C-8760/AI intercommunication-communication control panel. is used to clear an error and start over with the selection. The G button is used to select a guard channel. The three indicator groups display the following: HF FREQ—displays the selected frequency for the HF radio set CHAN UHF 1 FREQ—displays the selected channel and frequency for the UHF 1 radio set CHAN UHF 2 FREQ—displays the selected channel and frequency for the UHF 2 radio set The five switches are used to select what type of information the operator is inputting via the keyboard. After the operator inputs the channel or frequency, the ENTER switch must be pressed. The last section of the panel contains seven fault indicator lights. These indicators are labeled UHF1, UHF2, PRESS, HF, CPLR, DTS, and SLU. Each one is the fault indicator for the system or component for which it is labeled. It will illuminate when a fault occurs in its corresponding system or component. Located directly under the HF squelch knob is a BITE indicator. This indicator will illuminate when a fault is detected in the IRC. 1-3