Vivitar auto thyristor 5600 on a nikon D90?

My dad used to do a lot of photography and he found one of his old flashes that's a Vivitar auto thyristor 5600 and I have a Nikon D90 and i was wondering if that could work on my camera?

The trigger voltage of your Vivitar 5600 is likely to be very high and may damage your camera. If you really want to use it, invest in the WEIN HSHS Adapter - Hot Shoe to Hot Shoe Safe Sync which will reduce the trigger voltage of the 5600 to a safe 6 volts.

http://www.weinproducts.com/safesyncs.htm