Ademco 5881ENM receiver queston

["Robertm" <Respond@xxxxxxxxxxxxx>]

Adding an Ademco 5881ENM wireless receiver to my Vista 15P. All of the
documentation shows 4 wires connecting between the receiver and the panel.
However, the receptacle on the receiver has 5 pins and the plug has 5 wires,
not 4.  Green wire appears to be pin 1, black pin 2, red pin 3, blue pin 4,
yellow pin 5,  do I simply ignore the blue wire pin 4 on the receiver?

Bob