Echo API Library

The Echo API Library provides programmatic control of Echo Digital Audio test interfaces, including the Echo AIO and Echo ATS devices.

Supported Devices

Echo ATS

A precision audio test system with:

• 8 analog inputs with selectable gain (1x, 3x, 10x, 31x, 100x)
• 4 analog outputs with configurable modes (Line, Amplifier, Headphone)
• S/PDIF or Word Clock digital I/O
• 4-bit AUX GPIO
• Impedance measurement mode
• I2C passthrough

Echo AIO

A modular audio test interface with interchangeable audio modules:

• AIO-A - Analog microphone inputs with IEPE/CCP support
• AIO-S - Speaker monitor inputs
• AIO-L - Line level inputs/outputs
• AIO-H - Headphone amplifier outputs
• AIO-T - TDM digital audio interface

Installation

Windows

The Echo API Library is installed as part of the Echo Control Panel application.

Default installation path: C:\Program Files\Echo Test Interfaces\EchoAPI.dll

macOS

Download the Echo Control Panel DMG from support.echotm.com/ats/installer. When mounted, the DMG contains libEchoAPI.dylib. Copy this file to your project's working directory or a location in your library search path.

Quick Start

C/C++

#include "EchoAIOInterface.h"

int main()
{
    // Initialize the library
    AIO_initialize();

    // Check for connected devices
    if (AIO_isATSConnected())
    {
        printf("ATS connected\n");

        // Set input gain to 10x on channel 0
        AIO_setInputGainDirect(0, 10);

        // Enable CCP (constant current power) for IEPE microphones
        AIO_setConstantCurrentState(0, 1);
    }
    else if (AIO_isAIOConnected())
    {
        printf("AIO connected\n");

        // Get device info
        int numInputs = AIO_getNumInputChannels();
        int numOutputs = AIO_getNumOutputChannels();
        printf("Inputs: %d, Outputs: %d\n", numInputs, numOutputs);
    }

    // Shutdown
    AIO_shutdown();
    return 0;
}

Python

from echo_api import EchoAPI

# Initialize and use context manager for automatic cleanup
api = EchoAPI()
api.initialize()

try:
    if api.is_ats_connected():
        print("ATS connected")

        # Set input gain to 10x
        api.set_input_gain_direct(0, 10)

        # Get serial number
        serial = api.ats_get_serial_number()
        print(f"Serial: {serial}")

    elif api.is_aio_connected():
        print("AIO connected")
        info = api.get_device_info()
        print(f"Inputs: {info.num_inputs}, Outputs: {info.num_outputs}")

finally:
    api.shutdown()

Documentation

Document	Description
Getting Started	Installation and first steps
API Reference	Complete function reference
AIO Guide	Echo AIO device guide
ATS Guide	Echo ATS device guide
EchoAIOInterface.h	C/C++ header with API documentation

Repository Contents

EchoAIOExample/
├── README.md                    # This file
├── EchoAIOInterface.h           # C/C++ API header (authoritative reference)
├── docs/
│   ├── getting-started.md       # Installation and first steps
│   ├── api-reference.md         # Complete API reference
│   ├── aio-guide.md             # AIO-specific documentation
│   └── ats-guide.md             # ATS-specific documentation
├── C++/
│   ├── Windows/                 # Windows C++ examples
│   └── macOS/                   # macOS C++ examples
├── Python/
│   ├── echo_api.py              # Python wrapper
│   ├── examples/                # Python examples
│   └── README.md                # Python setup guide
└── Matlab/
    └── EchoAIO.mltbx            # MATLAB toolbox

Supported Platforms

Platform	Architecture	Library
Windows 10/11	x64	EchoAPI.dll
macOS 12+	Intel/Apple Silicon	libEchoAPI.dylib

Error Codes

All API functions that can fail return an integer result code:

Code	Name	Description
0	ECHO_AIO_OK	Success
-1	ECHO_AIO_NOT_INITIALIZED	Library not initialized
-2	ECHO_AIO_INVALID_INPUT_CHANNEL	Invalid input channel number
-3	ECHO_AIO_INVALID_OUTPUT_CHANNEL	Invalid output channel number
-4	ECHO_AIO_INVALID_PARAMETER	Invalid parameter ID
-5	ECHO_AIO_INVALID_BUFFER_SIZE	Buffer too small
-6	ECHO_AIO_NOT_FOUND	Device or resource not found
-7	ECHO_AIO_USB_COMMAND_FAILED	USB communication error
-8	ECHO_AIO_INVALID_MODULE_SLOT	Invalid module slot (must be 0 or 1)
-9	ECHO_AIO_NOT_SUPPORTED	Feature not supported by device
-10	ECHO_AIO_TEDS_DEVICE_NOT_FOUND	TEDS microphone not detected
-11	ECHO_AIO_INVALID_VALUE	Value out of valid range
-12	ECHO_AIO_MISSING_PARAMETER	Required parameter not provided
-13	ECHO_AIO_TIMEOUT	Operation timed out
-14	ECHO_AIO_INVALID_POINTER	Null pointer passed

Use AIO_getErrorString() to get a human-readable error message.

Support

For more information about Echo test interfaces, visit https://echotm.com/

License

Copyright (c) 2022-2025 Echo Digital Audio Corporation. All rights reserved.