Nikon SB-5000 Reference Manual page 7

Advanced Wireless Lighting
Wireless multiple flash-unit photography with CLS; multiple remote
flash unit groups can be controlled with the master flash unit.
Quick wireless control
A
Wireless multiple flash-unit photography in which the flash output
level ratios of 2 remote flash unit groups (A and B) can be easily
balanced
Direct remote wireless multiple flash-unit photography
Wireless multiple flash-unit photography suited to taking pictures of
a fast-moving subjects; the master and remote flash units fire almost
simultaneously because the master flash unit does not emit monitor
pre-flashes.
Link mode
Enables selection of communication type between Nikon Speedlight
and camera. Available selections are pairing and PIN code.
Pairing
Speedlight and a camera paired beforehand communicate.
PIN code
Speedlight and a camera with the same 4-digit PIN code
communicate.
A-6