FYI, ESPHome 2025.12.0 releasee added a new USB CDC-ACM Interface component that enables USB virtual serial port functionality and is bridge-ready (designed to connect USB serial interfaces to UART or other serial interfaces). That initially support up to 2 independent CDC-ACM interfaces per device:
That means could now in theory develop an ESPHome-based solution using an ESP32 development board with Ethernet PHY (even one supporting Power-over-Ethernet / PoE (like Waveshare ESP32-S3-ETH board) as Serial-over-IP proxy for any UART-over-USB adapter, including the ZBT-2 (or other Zigbee Coordinator USB dongles and Thread Border Router USB adapters).
USB CDC-ACM Support
The new usb_cdc_acm component enables USB virtual serial port functionality on ESP32-S2 and ESP32-S3 devices (#11687).
Key Features:
- Multi-interface support - Up to 2 independent CDC-ACM interfaces per device.
- Configurable buffers - Adjustable RX/TX ring buffer sizes.
- Line state callbacks - Notifications for DTR, RTS, baud rate, and other line coding changes.
- Bridge-ready - Designed to connect USB serial interfaces to UART or other serial interfaces.
Note that it is currently limited to 2 CDC-ACM interfaces per ESP32, and is at this time only compatible with ESP32-S2 and ESP32-S3, but that means that you could in theory develop a solution that uses a single development board with two USB-ports to connect both one ZBT-2 and one ZWA-2, (or two ZBT-2 adapters).
That is, you could develop a generic ESPHome-based universal USB-to-Ethernet Bridge, a USB to Serial-over-IP (Serial-over-LAN) proxy appliance compatible with standard Z-Wave Controller and Zigbee Coordinator USB adapters. See dicusssion about that idea here → Make an ESPHome-based universal USB-to-Ethernet Bridge, a USB to Serial-over-IP (Serial-over-LAN) proxy appliance compatible with standard Z-Wave Controller and Zigbee Coordinator USB adapters · tube0013/tube_gateways · Discussion #239 · GitHub
PS: The concept is that this could in practice work the same as ESPHome’s Z-Wave Proxy component but bridge any UART serial communicatuon traffic to and from an UART-USB-bridge adapter via a TCP socket in Home Assistant OS.
Architecture: Home Assistant ↔ LAN ↔ ESP32 with ESPHome proxy ↔ USB-UART-dongle
