When to Use 2000 vs. 5101

• Use squawk 2000 when you are flying VFR in uncontrolled airspace and are in two-way radio contact with a Belgian ATS unit (e.g. Brussels Info). This code indicates you are receiving a flight information service and are actively communicating with ATC.
• Use squawk 5101 when flying VFR in Class G airspace within the Belgian FIR (excluding Luxembourg), and you wish to listen to the Brussels Info frequency without initiating contact. This is ideal if you’re not requesting flight information services but want to stay reachable and contribute to safer, more efficient frequency use.

In short:
2000 = You are in contact and receiving FIS.
5101 = You are monitoring but not in contact, though still reachable.