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Dock 3 - 3.5 mm jack pinout

The Dock 3 features versatile external ports using TRS (tip-ring-sleeve) connectors, also known as 3.5 mm audio jacks. Each port supports multiple functions and operating modes.

The Dock 3 automatically detects the Unfolded Circle IR Blaster and IR Extenders. For Trigger and RS232 modes, please follow the port configuration as described below.

⚠️ Hot-plugging is not supported and may cause brownouts depending on the port configuration. Always connect accessories before powering on the device.

 

ports-ucd3.png

 

Supported Modes

Blaster Mode

Used to control devices via an Unfolded Circle IR Blaster.

  • Tip: Signal output

  • Ring: 5 V output (200 mA continuous)

  • Sleeve: GND

Extender Mode

For use with Unfolded Circle IR extenders. The Dock 3 supports old extenders from Dock 2 with mono-plug and new Dock 3 extenders with stereo-plug.

  • Tip: 5 V output (~20 mA limited)

  • Ring: Not connected

  • Sleeve: Signal (GND reference)

RS232 Mode*

Used for serial communication with compatible equipment.

  • Tip: TX (Transmit)

  • Ring: RX (Receive)

  • Sleeve: GND

Trigger Mode*

Allows external triggering with 5 V. The 5 V output is protected by a resettable PTC fuse.

  • Tip: Reserved

  • Ring: 5 V output (200 mA continuous)

  • Sleeve: GND

*RS232 and Trigger mode will be available with a software update.

Detection and Compatibility

  • The Dock 3 automatically detects supported accessories on startup by identifying the electrical signature of official Unfolded Circle hardware.

  • A manual mode override  will be available with a software update in future for use with custom setups.

  • Hot-plugging is not supported. Always connect accessories before power-up to ensure correct detection.

  • Only Dock 3 firmware supports automatic mode detection. 

  • When using custom-built equipment or cables (e.g. for RS232), ensure strict adherence to the TRS pinout shown above to avoid detection issues or damage.

Compatible Accessories

Official IR Blaster and IR Extender are available from Unfolded Circle.

 

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