Does anyone know of an RS-422 device that can
give VTR control with 3 JVC BR-HD50 Decks?
Lock/Sync the timecode for a 3 camera shoot?

IF you could find an old-school A/B Roll Edit controller you could control 3 decks, and concievable get them in sync (if you prestripe the tapes.) The only problem is that one would be in record and the other two would be playing. However, you might be able to manually put the two playing decks into record mode once they are running at speed?

How about a simple device for the input in the back
of the deck labeled: LANC?

How about a basic device that would just have VTR control
thru the RS-422 port?

Just a question but are you going to have 3 camera operators? Why not just sync off a visual cue? Like a camera flash? Without genlock you'll need some visual cue in order to sync.

Sometimes the cameras are in a hard to reach place
so, I thought I would have the 3 cameras feed into
3 decks and then have psedu-sync control over the
three decks. Plus the there would be alot of starting
and stopping of the recording.

...Plus the there would be alot of starting
and stopping of the recording.
That's what kills the visual cue sync. Once you stop the camera (any one of them) then it becomes a nightmare.

True, what are people using these days for a visual sync que?
Some type of flash device with a remote?

Having shot about 20 multi-camera concerts on DV (many of them being 7-8-9 cameras), you're much better off just letting cameras roll.

If I have a guy break roll during a concert more then once, that's when I have a talk. (or...consider having their right thumb removed!) :-)

With a little practice, it becomes pretty easy to sync multiple cameras as long as you have an audio reference on each camera. It sounds daunting and scary to just worry about syncing in post (and not during the shoot), but as long as no cameras break roll, you'll be fine.

[edit: ooops, just remembered this is a live to VTR situation. But if the idea originally was just to make post sync easier (and nothing else) then I guess I'll let my post alone]

There are a couple of ways to do it. If your NLE supports multicam then you'll need a visual cue like a flash or something that all camera's picked up. If you sync manually on a timeline then the audio waveform will serve as a sync.

Nate is right, if any camera breaks roll then it's thumb screws for the camera operator and nightmares for the editor. That is the only way I know to do it without bonafide genlock.

Wouldn't you just let the cameras TC go on freeroll so you aren't hurt by starting and stopping?

You're overthinking it a little. All you have to do is set one deck to Int TC set it to freerun(time of day is fairly standard). Set the other 2 to TC Ext, slave from the first. The trick is you always start recording on the Int TC deck first and stop it last. When you log your footage from the first deck you can use the exact same in and out points for all subsequent footage since they all have the same TC. And to answer your original question, yes they do make such a device but I've only used it once and I don't remember what it's called but it does exist. Good Luck, Jason.