Home Assistant Connect AUX-2 – Smart home multi-function accessory, 3.5 mm Jack, S/PDIF, RS-232, USB-C, USB-A, Bluetooth, Wi-Fi, PoE, white (NC-AUX-9758)

The Home Assistant Connect AUX-2 is a multifunctional Home Assistant accessory for audio playback, serial device control, remote placement of a Z-Wave adapter and Bluetooth LE Proxy functionality. It connects via Ethernet or 2.4 GHz Wi-Fi and can be powered through USB-C or an 802.3af-compatible Power over Ethernet connection.

The AUX-2 features both a 3.5 mm analogue audio output and an optical S/PDIF output, allowing existing Hi-Fi amplifiers and AV receivers to be integrated into Home Assistant. With Music Assistant, playback can be synchronised with other compatible network speakers. Both the analogue and digital outputs support 16-bit / 48 kHz stereo audio, while the digital output provides lossless PCM audio.

Its two RS-232 ports, USB-A connector and Bluetooth 5 LE Proxy make it possible to integrate a wide range of equipment through a single device. Televisions, AV receivers, projectors, uninterruptible power supplies and other controllable devices can be connected to Home Assistant over serial communication. The USB-A port can be used with the separately available Home Assistant Connect ZWA-2 Z-Wave adapter or a USB-to-RS-485 adapter. The device is based on ESPHome and its bootloader is unlocked, so it can also be used with custom firmware.

About Home Assistant and Nabu Casa

Home Assistant is an open-source smart home platform built around local operation, allowing devices and services from different manufacturers to be integrated into a unified system. The Connect AUX-2 is designed specifically for use with Home Assistant and is built on the ESPHome software platform.

The product is made by Nabu Casa, the organisation supporting the development of Home Assistant. The manufacturer provides dedicated support and long-term software updates, while revenue from product sales helps fund the continued development of Home Assistant.

Key product features

• Multifunctional Home Assistant accessory: Audio playback, RS-232 control, optional RS-485 and Z-Wave connectivity, and Bluetooth LE Proxy functionality in a single device.
• Synchronised audio: Multi-room synchronised playback can be used with Music Assistant and Sendspin.
• Analogue and optical audio output: A 3.5 mm analogue or optical S/PDIF output can be used; only one audio output can be active at a time.
• Two RS-232 ports: Two 3.5 mm RS-232 interfaces are available for controlling televisions, AV receivers, projectors and other serial devices.
• Bluetooth LE Proxy: The dedicated antenna can be used to forward Bluetooth Low Energy devices into Home Assistant.
• Power over Ethernet: Network connectivity and power can be provided through a single Ethernet cable.
• ESPHome-based system: Ready to use out of the box, while the unlocked bootloader also allows custom firmware installation.

Smart home protocols and platform compatibility

• Home Assistant: Designed specifically for Home Assistant; a working Home Assistant system is required.
• ESPHome: The device firmware is based on ESPHome.
• Ethernet: Wired network connectivity is supported.
• Wi-Fi: 2.4 GHz IEEE 802.11b/g/n connection.
• Bluetooth: Bluetooth 5 LE Proxy with up to 3 active Bluetooth connections.
• Z-Wave: Can be used with the separately available Home Assistant Connect ZWA-2 adapter.
• RS-232: Two direct serial ports are available.
• RS-485: Can be used with a separately available Waveshare USB-to-RS-485 adapter.

Smart features

• Home Assistant media playback: Audio can be sent directly from Home Assistant to the AUX-2 audio output.
• Music Assistant: Multi-room synchronised music playback can be used through the Sendspin protocol.
• Integration of legacy Hi-Fi equipment: Amplifiers and AV receivers with analogue or optical inputs can be used as network media players.
• Serial device control: Devices without their own network integration can be controlled through RS-232.
• Standby control: With suitable RS-232-compatible equipment, control may remain available even while the device is in standby mode.
• Bluetooth Proxy: Signals from Bluetooth LE sensors and other BLE smart home devices can be forwarded to Home Assistant over Ethernet or Wi-Fi.
• Remote placement of a Z-Wave coordinator: With the Connect ZWA-2 USB adapter, the Z-Wave interface can be positioned farther away from the Home Assistant server in a more favourable radio location.
• Custom firmware: The unlocked bootloader allows custom firmware installation and advanced modification of the device.

Audio features

• Analogue audio output: 3.5 mm stereo output.
• Optical audio output: Digital S/PDIF output.
• Analogue audio: 16-bit / 48 kHz stereo.
• Digital audio: 16-bit / 48 kHz stereo PCM with lossless transmission.
• Supported codecs: FLAC, MP3 and WAV.
• DAC: Texas Instruments PCM5122 with a 112 dB signal-to-noise ratio.
• Output usage: Only one of the analogue and optical audio outputs can be used at a time.
• Audio direction: The audio connectors operate as outputs only.
• Bluetooth audio: The Bluetooth connection cannot be used for audio transmission.

Serial and USB interfaces

• RS-232 ports: 2 × 3.5 mm RS-232 connectors.
• RS-232 signal level: ±5 V.
• TX/RX configuration: The TX/RX assignment of the serial ports can be switched.
• USB-A: Used for connecting external USB devices.
• Connect ZWA-2: A separately available Z-Wave adapter can be connected to the USB-A port.
• RS-485: Can be expanded with a Waveshare USB-to-RS-485 adapter; the adapter is not included.

Power supply and network

• USB-C power supply: 5 V DC / 2 A.
• Power over Ethernet: Works with IEEE 802.3af or newer PoE standards.
• Ethernet + USB-C: On Ethernet networks without PoE, the device can be powered separately through USB-C.
• Wi-Fi + USB-C: When using a wireless network connection, USB-C power can be used.
• Typical power consumption: Less than 1 W.

Technical specifications

• Product name: Home Assistant Connect AUX-2
• Model number: NC-AUX-9758
• SoC: ESP32-S3R8
• PSRAM: 8 MB
• Flash memory: 8 MB
• Audio DAC: Texas Instruments PCM5122
• DAC signal-to-noise ratio: 112 dB
• Ethernet controller: W5500
• Wi-Fi: 2.4 GHz, IEEE 802.11b/g/n
• Bluetooth: Bluetooth 5 LE
• Bluetooth Proxy: Up to 3 active connections
• Ethernet: Supported
• PoE: IEEE 802.3af or newer
• USB-C power supply: 5 V DC / 2 A
• Typical power consumption: Less than 1 W
• Analogue audio: 16-bit / 48 kHz stereo
• Digital audio: 16-bit / 48 kHz stereo PCM
• Audio outputs: 3.5 mm analogue and optical S/PDIF
• RS-232: 2 × 3.5 mm, ±5 V
• USB-A: 1
• Firmware platform: ESPHome
• Bootloader: Unlocked, custom firmware can be installed
• Dimensions: 106 × 63 × 25 mm
• Housing material: Polycarbonate
• Colour: White and semi-transparent
• Operating temperature: 0–65 °C
• Installation environment: Indoor only
• Certifications: CE, FCC, RCM
• FCC ID: 2A8ZE06
• EAN: 0860011789758
• UPC: 860011789758
• Country of origin: China

Additional features

• Setup: When connected to a Home Assistant system, the setup process guides the user through configuration.
• DIY options: The factory firmware is ready to use, while the ESPHome base and unlocked bootloader also allow advanced users to make custom modifications.
• Package contents: Home Assistant Connect AUX-2, warranty and safety information, Home Assistant sticker.