Nikon SC 29 off-camera flash cord ($80)

I have never found the light from a camera mounted flash acceptable, so I have always used a cord. In dark interiors, this has made the focus assist beam useless. Now that I have the cord with the assist beam, I can focus in complete darkness as fast as anywhere else. This beam even works from across a large dance floor at a wedding reception. If you are a wedding photographer and you are frustrated with bad auto focus results in dim interiors, you will love this cord. The auto focus performance becomes dreamlike.

I purchased an SC29, and it may just be me, but I can't get it to work. Seems that it would be simple - attach flash on one end, and attach cord to hot shoe. My SB800 will flash, but every shot is a full power pop. No TTL. I've read that a fair number of these cords are defective. Looks like I'll be sending mine back for another, too. Hopefully second time is a charm??