If it is a QBUS grant continuity card, it will have two looped-back pin pairs (the QBUS has two grant lines - DMA and interrupt) on the back-side, with a blank pin between them. (AM2-AN2 and AR2-AS2, to be exact.) All the DEC 40-pin serial line headers have the same pintout, AFAIK. So you can use any of the manuals for the DL11, e.g. EK-DL11-OP-001, available widely, e.g.: http://vaxhaven.com/images/4/42/EK-DL11-OP-001.pdf which uses that same pinout, and has it in great detail, for making a cable. Those directions produce at DTE cable - if you want to produce a DCE (suitable for plugging into another computer), you need to reverse RD and TD, etc. Noel