The AI-S (ASTi Interface - Single) is a compact audio and I/O distribution device that connects remotely located operator headsets, speakers, control panels, and other peripherals to the Voisus network via Ethernet.

AI-S Hardware Diagram:


  • Stereo Support: Stereo operation (independent left and right output) is supported on a single connector, reducing cabling complexity and installation footprint for applications requiring stereo operators.

  • Reduced Footprint: The AI-S has a compact footprint and fits easily on a desktop.

  • Software Configurable: Adjustable preamp gains and sidetone for easy, direct connection to a variety of audio/communications systems and peripherals.

  • Serial Data Port: Provides a convenient control interface for ASTi Hand-Held Terminals (HHTs), simulated panels, and live radio control.

  • Integrated I/O: Configurable digital and analog I/O for direct connection of PTT units, volume controls, switch detection, radio PTT activation, and other control applications.

Physical Specifications

  • AI-S Front Panel:

  • AI-S Rear Panel:


Dimensions without connectors: 4.860" L x 2.965" W x 1.17" H


A packaged AI-S weighs 5oz.

Power Requirements

  • The AI-S is powered through the Ethernet port via Power over Ethernet (PoE).

  • Power Consumption: <10w @ 56VDC

Serial Connection

  • RJ-12 Pinout for RS-422 Mode

  • RJ-12 Pinout for RS-232 Mode

Audio Interface Pinout

  • DB-15 Connector Pinout Diagram

Status Indicator Lights

The AI-S LED indicator light displays AI-S status.

LED Light Status
Solid Green Normal operation
Flashing Blue Boot mode

Audio Input and Audio Output

Audio Input
Characteristic Value
Input Impedance 4.6 k
Max. Input Level 3.25 Vpp max (6.5 Vpp differential)
Input Gain 0dB, +9dB to 60dB, software configurable (see Note 1)

Note 1: The AI-S gain covers a total gain range of 60dB. The range 9dB to 60dB can be set in 3dB steps. The range 0dB to 9dB cannot be selected as a function of design.

Audio Output
Characteristic Value
Output Power 150 mW per Channel at 16 Ω
Max. Output Signal 5 Vpp

Control Input and Digital Output

Control Input

The control inputs are contact sensing; no voltage is required. Simply connect the control input and control input ground lines together using a switch or other suitable device, such as a press-to-talk (PTT) device. The control input can logically function as either a digital input or an analog input.

Control Input Circuitry

Control Input Used as Digital Input

To use the Control Input as a Digital Input, simply short or open the required pins. For example, if you short pins 9 and 10, Control Input 1 will be True. If the pins are open, Control Input 1 will be False. In this example the control input acts like an on/off switch.

Control Input Used as Analog Input

The control input can be used as an analog input by inserting a resistance between the control input and control input ground pins. The 4-channel selector knob, for example, contains a switch that is used to change the resistance between the control input and control input ground pins.

Digital Output

The digital output circuitry consists of an opto-isolated, solid-state relay for switching power to external loads.

Type Opto-isolated FET
Maximum Continuous Current Rating 120 mA
Maximum Power Dissipation 300 mW

Digital Output Circuitry

Additional Information

Memory Devices

The AI-S memory devices are summarized in the table below.

MCU Internal SRAM 96kB SRAM
MCU Internal 512 kB

Temperature & Humidity Ranges

The AI-S temperature and humidity ranges are summarized in the table below.

Type of Range Suggested Range
Operating Temperature Range +10°C to +32°C (50°F to 90°F)
Operating Max. Temperature Gradient 20°C (68°F) per hour
Operating Humidity Range 10% to 70% non-condensing
Storage Temperature Range 0°C to 55°C (32°F to 135°F)
Storage Max. Temperature Gradient 30°C (86°F) per hour
Storage Humidity Range 5% to 95%


Typical System Mean Time Between Failure (MTBF): 1,970,288.06 hours

Typical Headset Settings

  • Typical Mono Headset Connection:

  • Typical Stereo Headset Connection:

Warranty Information

  • The equipment is covered by warranty for a period of one year following purchase. In the case of equipment upgrades, the warranty applies to original date of shipment of individual components.
  • Other commercial equipment purchased or provided such as monitors, amplifiers, speakers, and fiber optic links are also covered under the one year warranty unless otherwise stated.
  • The warranty does not cover improper equipment handling or improperly packaged returns. Extended warranties are available. Contact ASTi for details at (703) 471-2104.

Repairs and Returns

If it becomes necessary to return the equipment to ASTi, please observe the following instructions:

  1. Request an RMA number through the ASTi website:

    The receiving team at ASTi will not receive a repair without an RMA number.

  2. When packaging the equipment for return, make sure it is well protected. ALWAYS DOUBLE-BOX THE EQUIPMENT. The inner container should employ some semi-rigid, contour-fitting foam, while the exterior container should use a more pliant, shock-absorbing material such as styrofoam peanuts. The device should be properly enclosed in an anti-static bag to prevent possible ESD damage. Failure to properly package the equipment during shipping could void the warranty.

  3. Do not ship accessory pieces such as rackmount kits, power supplies or software. Only include items that do not work.

  4. The shipping label must include the RMA number.

  5. Include a description of the problem including the serial number for the unit in question. Include point-of-contact information including name, telephone number and equipment return address. Failure to include this information could extensively delay the return of the equipment.