"Our" compatibility means that there is a least one directional passive (not powered) interface between two active (powered) devices.
Example 1. A camcorder with a Firewire output is compatible with a recorder with a Firewire input.
If one device is passive it can be directly connected to the other device.
Example 2. A camcorder with a Firewire 4 pin female connector is compatible with a 4 pin Firewire male plug.
We think that "absolute" compatibility is unreachable. We think that any two compatible devices will always have an imaginable interface which works with one and does not work with the other.
Example 3. A camcorder has both Firewire and SDI outputs and a recorder has Firewire input but no SDI input. So they are compatible through Firewire but not compatible through SDI. We will still list them as "compatible".
Please note we do not consider all possible interfaces for each device, but only those we consider important.
The above means that if you need a specific compatibility between two devices you should not rely on our "common sense" compatibility.