I may already have the answer to this but I am just making sure. I have watched a few video's that kinda explain how to Jam Sync TC from the Sound Device 744T to the Arri Alexa.

If I am right, you need to connect a 5 pin Lemo cable from the Time Code in/out and connect it to the 5 pin Lemo TC input on the Arri Alexa. From there, you access the TC on the Alexa and countdown to make sure the TC's are in sync.

Am I correct in this? If not, it would be much appreciated if you could shed some new light on this.


1 Answer 1


I've only jammed Alexa from my 633 but there is a few steps you need to take when jamming any camera!

  1. You probably want to make your 744 the master timecode source so make sure it is set up to send timecode-rather than receive.
  2. You need to let the Alexa know you want it to be a timecode "slave" so you need to go into its menus an select "receive timecode" etc. I imagine it will be easiest if you set it to "24 free run" or similar as then you will only need to jam it-rather than send a continuous signal. Also make sure frame rate settings are correct and the same on both devices.
  3. It is indeed Lemo 5 pin I believe so make sure you have a cable suitable.
  4. Plug in to both your SD and Alexa (on most cameras this will JAM automatically but I cant remember if the Alexa does this)
  5. Check the timecode manually by comparing on your LCD to the Alexas (or get your friendly cam assistant to read out the display in real time)
  6. Make sure to jam again at lunchtime and check to see if it has drifted (if it has you should consider a lockit box or wireless timecode receiver but the Alexa is better than other cameras.

Let me know how you get on! :)

Here's a handy page! - http://soundrolling.com/timecode/how-to-timecode-jam-arri-alexa/

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