Audio Control Unit
The Palomar Products Audio Control Unit (ACU) provides access to radio and intercommunication channels within a limited amount of panel space. This unit permits access of up to 30 radio and/or intercom channels assignable to the panel pushbuttons.
Panel operation is very user friendly. The receive audio is selected via simple pushbutton keys. The receive volume levels are preset to a nominal value by the communications plan resident in the Communications Control Unit (CCU), and can be individually attenuated from 0 to 20dB at the ACU with momentary pushbuttons. A master volume control provides an additional 30dB attenuation to the composite audio baseline. Pulling out the master volume control knob activates transmissions on the emergency Override (CALL) intercom net.
The unit displayed on this page has been configured for the flight engineer and observer positions of a P-3. It allows each user to communicate over four intercom nets and to monitor radio channels.
The unit can also be used in other applications where transmissions on radios is needed and panel space is at a premium. Channel buttons can be used to select radio channels for receive or transmit. The LEDs over each button can indicate radio, receiver, and transmitter selection as well as receiver and transmitter activity.
The selector keys use filmstrip technology, which allows button legends to be changed quickly and inexpensively when upgrading systems.
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28 VDC per MIL-STD-704
Receive: ±3dB from
40Hz to 18kHz
Transmit: ±3dB from
300Hz to 10kHz
(at radio channel output)
< 0.5 mVrms
(typical 28 VDC)
Electronics: 10 Watts
>160,000 hours MTBF
Environmental Requirements per MIL-E-5400T
-54° C to +55° C at sea level -54° C to +40° C at 30,000 ft
-54° C to +71° C at sea level
-54° C to +57° C at 30,000 ft
-62° C to +85° C at sea level
Up to 95 percent relative
Per MIL-STD-810C, Method 514.2, Procedure I, Category C Equipment
Compliant to NACSIM 5100A
Per MIL-STD-810C, Method 516.2 - Procedures I, III, IV
Designed to provide EMP protection to customers-specified levels
Night Vision Goggle Compatible
Up to Three LED Indicators Over Each Channel Select Button
Integrated Panel Crew Station Unit
The CSU provides crew members with the acoustic and visual man-machine interface to the intercommunication networks and external radios.
The IPCSU was developed to provide access to a large number of communication channels within a limited amount of panel space. This unit permits access to 30 radio channels and intercom networks. The selector buttons use film strip technology which allows button legends to be changed quickly and inexpensively when system upgrades occur.
Panel operation is very user friendly. The receive audio is selected by simple button push. The receive volume levels are preset to a nominal value by the communications plan resident in the Communications Control Unit and can be individually attenuated from 0 to 20 dB at the IPCSU with momentary push-buttons. A master volume control provides an additional 30 dB attenuation to the composite audio baseline.
A transmit status light above the selected transmit key indicates which radio or intercom net is currently selected for transmission. The current transmit radio selection is changed by simply depressing the key corresponding to the desired transmitter selection. The receive function is automatically selected when an asset is selected for transmit.
The receive status light will illuminate and the volume of the associated transmit channel will be automatically set to -10 dB or to the level previously selected, if the volume has been adjusted since power-on.
The operator can communicate with any other position on any one of several intercom nets. The operator places a call by depressing the switch corresponding to the desired network. The emergency call net may be selected by the operator by pulling out the VOL/CALL switch.
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18 Watts nominal at 28 VDC
(typical) >80,000 MTBF
28 VDC per MIL-STD-704A Notice 3, Category
>120 dB at 1 kHz when used with high isolation headset
(1 kHz Reference)
0.5 dB from 300 to 5000 Hz
91% by Diagnostic Rhyme Test during peak ambient noise conditions of 105 dBa
(300 Hz to 5 kHz)
Length x width x height
6.50 x 5.75 x 6.00 inches
(maximum) 6 pounds
-54° C to +55° C at sea level
-54° C to +40° C at 30,000 ft
Night Vision Goggle Compatible (Gen II and III)
Cross-Band or In-Band
Liquid Crystal Crew Display Unit
The Liquid Crystal Crew Display Unit (LCCDU) provides the operator with access to, and control of assigned communications assets.
The LCCDU provides monaural or binaural capability as required to each position equipped with a LCCDU and provides the microphone interface to the Communications Control Unit (CCU).
Through the full function keyboard, the LCCDU features control of the transmit and receive functions including the control and reassignment of all communications assets, crypto assignments, and Built-In-Test (BIT) readouts. Complete status of the communications assets for each operator is available through the eight color liquid crystal display. Each LCCDU is identical and completely interchangeable with any other position location. The CCU may be programmed in real-time if necessary to allow or disallow access of any given asset by any given crew position via the LCCDU.
The integral display intensity control is capable of adjusting the display brightness from off to full intensity without external controls or potentiometers. The LCCDU interfaces with the CCU via a serial RS-422 control data twisted-shielded wire pair.
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24 Watts nominal at 28 VDC
(typical) >10,000 MTBF
(1 kHz Reference)
3dB from 20 Hz to 18 kHz
-30° C to +55° C at sea level
-30° C to +40° C at 30,000 ft
-40° C to +85° C at sea level
Dual Crew Position Capability
Intercommunications Set Control
The Intercommunications Set Control (ISC) provides each crew member with receive and transmit access to assigned radios and intercom channels.
The ISC contains the controls to monitor radio and intercom channels, adjust each channel volume independently and select transmit channels. Receive audio is selected and volume level adjusted by ten identical control knobs. Each control is a rotary switch with seven detent positions providing attenuation from 0 to -20 dB in 3.3 dB increments. A master volume control provides an additional overall composite audio attenuation range of 30 dB. A seven position rotary transmit selector switch provides for transmit selection of intercom and radio channels. A three position ICS switch selects the keying mode. HOT MIC enables continuous keying on the intercom net PTT and permits the external PTT to key the appropriate channel. CALL is a spring loaded position which keys the emergency CALL intercom net. In the normal mode, the operator can select a radio for transmission, press the Radio PTT and talk on the radio, or press the ICS PTT and talk on the NORM ICS net. If a single cordset PTT is used, the PTT will follow the transmit selected position requiring the operator to select the desired radio or intercom channel. With a radio selected and the ICS switch in the HOT MIC mode, the operator can talk on the NORM ICS net. With the external PTT pressed, the ICS transmission will be automatically interrupted and voice transmission will be transferred to the selected radio. The CALL position has priority over other keying and provides direct access to all other crew members at an enhanced volume level, adjustable only by the listener master volume control.
10 Watts nominal at 28 VDC
15 Watts nominal at 5 VDC (Panel Illumination)
(typical) >68,000 MTBF
28 VDC per MIL-STD-704A Notice 3, Category B
Just an FYI.
4.0 x 5.75 x 3.75
6.50 x 5.75 x 3.75 inches
Dual Crew Position
Communications Control Unit
The Communications Control Unit (CCU) is a modular microprocessor controlled switching unit that provides the interface between the aircraft communications suite and individual crew stations.
The CCU performs all switching and mixing of audio channels in accordance with a predetermined communications plan. The communications connectivity plan resides within the CCU, and is downloaded from Read Only Memory (ROM) to Random Access Memory (RAM) at power-on. This feature allows limited redirection of communications assets by a higher order controller via discrete input signals to the CCU.
Transmit and receive audio, along with the digital control signals are interfaced from the Communications Switching Unit (CCU) to each crew station via three twisted-shielded wire pairs per station. This interface technique eliminates the need for multiple and bulky cable installations, resulting in a reduction in overall system installation weight.
The Palomar Products Audio Mixer Device provides channel to channel isolation in excess of 150 dB. In addition, a firmware interlock can prevent the reception of any selected audio from being received at a given crew station when it is necessary to preclude headset to microphone coupling.
Audio traffic from all crew stations is controlled by the CCU in normal operations. A back-up control, initiated via an Emergency Audio Panel (EAP), bypasses the CCU to provide hardwired access to a set of predetermined radios. This feature allows safety-of-flight and some mission critical communications to exist in the unlikely event of a catastrophic failure of the intercommunications system.
(typical) 19,000 MTBF
Length x width x height
19.62 x 4.91 x 7.62 inches
(maximum) 18 pounds
Serial Data Bus Interface
Full ATR-Standard Communications Control Unit
The Communications Control Unit (CCU) is a dual microprocessor controlled modular audio switching and control unit that provides the interface between the communications suite and the individual crew stations.
The CCU performs all switching and mixing of audio channels in accordance with a predetermined communications plan. The communications connectivity plan resides within the CCU, and is downloaded from Read Only Memory (ROM) to Random Access Memory (RAM) at power-on. This feature allows the communications connectivity plan to be reconfigured in real time. Reconfiguration is accomplished either by direction from a higher order controller (i.e. via MIL-STD-1553B data bus), or by direction received from a Palomar Products Crew Station Unit or Crew Display Unit.
Transmit and receive audio, along with the digital control signals are interfaced from the CCU to each crew station via three twisted-shielded wire pairs per station (four, if interfacing is to a binaural station). This interface technique eliminates the need for multiple and bulky cable installations, resulting in a reduction in overall system installation weight.
Audio traffic from all crew stations is controlled by the CCU in normal operations. A back-up control, initiated via an Emergency Audio Panel (EAP), bypasses the CCU to provide hardwired access to a set of predetermined radios. This allows safety-of-flight and some mission critical communications to exist in the unlikely event of a catastrophic failure of the intercommunications system.
90 Watts nominal at 28 VDC
(typical) >8,500 MTBF
(maximum) 40 pounds
-52° C to +85° C at sea level
Cross-Band and In-Band