Thanks M_c
Balazs from uccnc got in touch with me and said pretty much the same. The pin 3 on the rj45 socket i'll wire to Dir- and link Dir - to the Pulse - . Its a shame they didn't use the pin4 on the rj45 socket as an extra contact to simplify the wiring . Although I suppose I could just bridge the pads on the circuit board between pins 3 and 4 or just link at the stepper driver (probably easier) I wish the manual for the hdbb2 was a bit less technical. For simple folk like me

Thanks for your help

Andrew