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Red Updates Sync Trigger Protocol

dsmc epic raven red scarlet start/stop sync trigger weapon

A Bit of History

Ever since the introduction of the Epic, triggering Red cameras has been a thorn in the side of camera assistants on professional productions across the globe. Over the years camera remote start triggering has shifted toward an open collector protocol more commonly known as momentary ground. Arri, Sony, Panasonic and most other modern cinema production cameras use this protocol. The other predominant protocol for modern cameras is the LANC protocol, which uses bidirectional serial communication, but we can leave that protocol for another day.

On the DSMC body, Red opted for their own protocol for remotely triggering the camera (Red calls this the Sync Trigger.) The Red Sync trigger used a 3.3V (5V tolerant) Schmitt trigger to start and stop the camera. This was frustrating for ACs not only because they had to buy a whole new set of cables for Red DSMC cameras, but also because those cables needed to be powered in order to trigger the camera. Some MDRs had the ability to output power, but most did not. This led to cables that either needed regulation, power injectors, or both.

And Now We Have DSMC²

With the introduction of the DSMC² body, the I/O has been completely removed from the camera brain and resides on what Red calls Expanders (Red's update to what they had been calling Modules on the first generation DSMC body). This allows the user to choose what I/O they would like to utilize and what form factor they would prefer for them. The first Expander Red released, called the Base Expander, featured all the connectors that had previously been mounted on the camera body. This Expander was also the last Expander to feature a Schmitt trigger. This is where things get a bit tricky.

For all the Expanders released after the Base Expander, Red has updated its trigger protocol to match Arri standard momentary ground. This is important for a few reasons:

  1. Legacy cables will not be able to be used on new Weapon expanders
  2. Cables with the new protocol will not work with first generation DSMC modules or the Weapon Base Expander
  3. Not every Weapon Body will necessarily be using the new protocol - The Base Expander uses a legacy Schmitt trigger 

What Can We Do?

Media Blackout prides itself on creating unique designs and solving problems for camera dept. As of this writing, we are able to wire any Red cable for either protocol, but changes on the website will take a bit of time. Don't worry, if you order a Red RS cable, we will contact you with options to get the protocol you need.

Since the new protocol is an open collector, legacy cables shouldn't cause damage if they're made correctly for the first generation DSMC bodies. The same is true if you use a cable made for momentary ground on legacy equipment.

If you are looking to get legacy cables rewired, order cables with the new protocol, or make adapters to use both, please contact us.

Media Blackout now offers the Red Schmitt to Pulse Adapter, which adapts legacy cables with the new protocol:

Update - 06/09/16

I have received many questions on how to set the camera to use the new protocol. According to Red, you can keep the same settings as you would for the old style trigger:

Camera Input: General Purpose In
Brain GPI In High: Record Start
Brain GPI In Low: Record Stop
Camera Output: Sync Out

Red also says that these settings will work:

Camera Input: General Purpose In
Brain GPI In High: Record Toggle
Brain GPI In Low: Disable
Camera Output: Sync Out

Media Blackout has updated product pages for trigger cables to reflect the new protocol or to give a choice between protocols:

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