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Latest Firmware Version: 2.17

Technical User Guide

The following information is pulled from the ACU2 Technical User Guide. For a comprehensive overview of the ACU2, please see the full guide:

View Guide

The ACE Communication Unit – 2nd Generation (ACU2) is a compact 48 kHz digital and audio distribution device that connects remotely located operator headsets, speakers, control panels and other peripherals to a central Telestra server via the ACENet architecture. The ACU2 evolved from the ACU to provide four-channel stereo support in a reduced size.

A comprehensive overview of the ACU2 can be found in the Technical User Guide

General Specifications

Compatible with Voisus, Telestra
Part Number ACU2-04-XX
Dimensions 7.9" length (depth) x 7.489" width x 1.724" height
Weight A packaged ACU2 weighs 2lbs. The included power supply weighs 0.5 lbs
Power Source Individual power supply, included.

Note: When daisy-chained, the ACU2 requires a different power supply. Contact ASTi for details.

Power Consumption +15VDC, 2 A
Mean Time Between Failure (MTBF) 108,100.75 Hours (COTS)
48,390.23 Hours (military)

Audio Input/Output

Audio Input

Impedance 4.6 kΩ
Max Input Level 6.5 Vpp
Gain -8dB, +2dB to +57dB, software configurable*
Microphone Power +12.5 VDC, software-enabled
Frequency Response 20 Hz to 20 kHz, +/-1.5dB

* The ACU2 gain covers a total gain range of 65 dB, with the range of +2 dB to +57 dB being settable in 1 dB steps, with -8 dB being available for input signals of greater than line level. The range -8 dB to +2 dB cannot be selected as a function of design.

Audio Output

Impedance 10 Ω
Current 0.15 A
Gain -25dB to +10dB
Level 2.2 Vpp (1.68 VAC RMS) into 8 Ω
Power 0.32 W at 8 Ω
Frequency Response 20 Hz to 20 kHz
Max Output Signal 5 Vpp

Memory Devices

This device works as a transportation mechanism, passing audio from one device to another until it reaches the headset or computer; this device does not store the audio.


Type Size User Modifiable Function Process to Clear
Micro-controller Internal SRAM 69 KB No Used as RAM for an internal MCU Remove Power
Count to 30
Restore Power


Type Size User Modifiable Function Process to Clear
Micro-controller Internal 256 KB Yes Firmware None
Flash 8 Mb Yes Firmware None


RJ-12 Pinout for RS-422

(Serial Connection)

RJ-12 Pinout for RS-232

(Serial Connection)

DB-15 Connector

(Audio Interface)


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