Marcell, A.K.A Fiberstrobe came up with a way to add a sync chord to any strobe that has an optical slave. In his case it was everybody’s lovable hackable strobe – the YN-460II. It synched wonderfully indoors but failed to fire under strong sun.
The YN460 does not have a PC or a 1/8 jack so actually an optical sync is the only solution if you are unwilling to add an external hot-shoe.
But, they don’t call him fiberstrobe for nothing. Using Velcro, cardboard and foamies, Marcell created an optical sync wire that works on light rather than closing an electrical circuit.