Hardware & signal path
Pro DJ Link
Pro DJ Link is the Ethernet network that joins several players and a mixer. One USB stick feeds every deck, the players share tempo and beat position, and lighting or recording software can read the whole rig from one connection.
In practice
One stick feeds every deck, and one bad Ethernet cable takes a player off the network silently.
Give every player a unique number — two decks claiming player 1 is the most common reason a link refuses to form — and look for the link indicator on each before you rely on browsing from one stick. When a deck drops off the network it does not stop playing; it just stops seeing the library, which reads as a software fault and is almost always the cable or the switch. Carry a spare patch lead if you tour with your own rig, and plug the stick into the player you can reach.
Up to 4 players
What the network joins
One stick
What it saves you carrying
Unique player number
The usual failure
Where these come from: Networking conventions for linked club players, not catalog figures — nothing we store describes a booth. For what we can measure, see what shared beat position is used for.
Why it matters
The single-stick part is the one you feel every night. Without link you carry a stick per player and keep them identical; with it, one stick in player one is visible from all four, and browsing happens once.
The shared beat position is what makes quantised cues and sync across decks possible at all. Everything the players do together — the beat counter, the phase display, sync — travels on this network rather than through audio.
Frequently asked
What is Pro DJ Link used for?+
Sharing one USB stick across every player, sharing tempo and beat position between decks, and giving lighting or recording software a single connection to the whole rig.
Do you need a switch for DJ link?+
For more than two devices, yes — the players connect through an Ethernet switch, and many club mixers have one built in. Two players can often be joined directly.
Why can only one player see my USB?+
Almost always the network rather than the stick: a duplicate player number, an unplugged patch lead, or a switch that has lost power. The deck keeps playing while it loses the library, which hides the cause.
Related terms
CDJ
A CDJ is the club-standard media player: a jog wheel, a pitch fader, hot cues and a waveform display, playing from a USB stick, an SD card or a laptop. It carries no mixer of its own.
Standalone player
A standalone player reads music straight from a USB stick or SD card. The decoding, the display and the cueing all happen inside the player, so nothing about the performance depends on a computer being awake.
Sync
Sync matches one deck’s tempo to the other automatically and holds it there, using the beatgrid the software calculated. It removes the arithmetic of beatmatching, not the decision about which record follows which.
USB prep
USB prep is exporting the tracks, grids, cue points and playlists you need onto a drive a club player can read. What is not exported does not exist once you are behind the decks.
Explore: Mixing guides · Sync · BPM tapper · All DJ terms