RB67 Dual Shutter Release Cable - What does it do?

Okay, this may be a bit remedial for many here, but I'm really curious to what exactly the dual shutter release cable does. My assumption is that it fires the mirror first, then fires the shutter. Does it turn the "T" shutter mode into more of a "Bulb" mode? Does it have any effect on "T" mode at all?

Your first assumption is correct. But you might as well use a much cheaper regular cable release on the lens, after releasing the mirror by hand. The double-release does not do anything else.

Roman

Right... I always used two separate releases.