# Connection Diagram and External Pulse Characteristics

- For connection convenience, a LEMO 6-PIN connector is used. The pinout and description of the LEMO 6-PIN connector are provided below:
    
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    - GND – Ground
    - 3V3 – Output line of regulated external 3.3V power
    - Time Mark – Input signal line for camera shutter trigger
    - Vin (5..18V) – Receiver input power from 5V to 18V
    - Shot control (for Sony cameras) – Output signal for controlling Sony camera shutter
    - n/a – Not assigned
    
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![](https://knowledge.topodrone.com/uploads/images/gallery/2024-03/embedded-image-bwbxweli.png)

When the TOPODRONE UAV PPK UPGRADE Kit is powered on and has completed initialization, it expects Falling Edge type pulses on the TimeMark pin, indicating the shutter trigger moment. The external pulse duration must not exceed 20ms. The TOPODRONE UAV PPK UPGRADE Kit also has an internal pull-up resistor, pulling the pulse voltage level to 3.3V.