Nikon D780 DSLR Camera (Body Only) - Manual (Page 527)

481 Remote Flash Photography
4
C : Choose a link mode.
Select [ Wireless remote (WR)
options ] > [ Link mode ] in the setup
menu and choose from the following
options:
Option Description
[ Pairing ]
The camera connects only to devices with which it has
previously been paired, preventing signal interference
from other devices in the vicinity. Given that each
device must be paired separately, [
PIN ] is
recommended when connecting to a large number of
devices.
[ PIN ]
Communication is shared among all devices with the
same four-digit PIN, making this a good choice for
photography featuring a large number of remote
devices. If there are multiple cameras present that
share the same PIN, the flash units will be under the
sole control of the camera that connects first,
preventing all other cameras from connecting (the
LEDs on the WR-R10 units connected to the affected
cameras will blink).