Yamaha PM5D Redundancy Manual page 2

Concept
In mission-critical applications such as live TV broadcasts to millions of
viewers, it may be necessary to have a spare mixing console
connected to the audio system with all the same inputs and settings as
the main console. Then in the event of an accident or failure, it is quick
and easy to swap from main to spare console and continue mixing
without interruption.
This concept will work with all of Yamaha's current range of digital
mixers, but for this example DM2000 will be used. The procedure is
basically the same with all the other digital mixers, with just small
variations in the Display menus and Setup functions.
Preparation
1. Obviously both consoles need to be identical, and with the same
MY-cards installed.
2. All inputs (analog and digital) need to be split to both consoles.
3. A memory card or a PC running Studio Manager software is
needed to transfer the memories from the main console to the
backup console.
4. 2 MIDI cables need to be connected between the two consoles:
2 YAMAHA Digital Mixers: A Redundancy Guide
Console #1 OUT to Console #2 IN;
Console #1 IN to Console #2 OUT.