# Connect the Camera Trigger

Please note 42L does not have Relay-to-PWM module, the Factory default triggering method is PWM, unless user contact ADTi tech support service before purchasing. It is either Relay (TTL) or PWM trigger, but it can be changed from PWM to TTL by flashing the camera firmware (please read <mark style="color:orange;">\[How to Flashing ADTi camera firmware]</mark> section to see the details).

<figure><img src="https://1360851269-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1vUos9NvEuROc8X0YHjh%2Fuploads%2Fzt8rjeQEfYcVHkcgrpDz%2Fd5f21f696627410f53af6cdddd954a2.png?alt=media&#x26;token=30c542f4-605a-4f43-9b7a-060548a7dcf6" alt=""><figcaption></figcaption></figure>

Please check Portal [<mark style="color:red;">\[ADTI PX4 or Ardupilot Setup\]</mark>](https://docs.adti.camera/adti-camera-px4-or-ardupilot-setup/)<img src="https://1360851269-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1vUos9NvEuROc8X0YHjh%2Fuploads%2Fxt1F6no5vCA7LVEpv7Gs%2F1698878258332.jpg?alt=media&#x26;token=c5149989-d6f1-48e0-940e-df6fc34496a1" alt="" data-size="line">for triggering camera by autopilot.