I was wondering if there was a default VLAN, like Cisco have VLAN 1 as their default ?
Default is the wrong term to use (although also commonly used). All ports on a VLAN capable device (switch, router, AP, etc.) start with a (so called) default VLAN ID (often ID 1) but are
untagged so the tag isn't used. VLAN ID tags only matter once you have more than 1 VLAN and traffic is being controlled (limited, routed, etc) based on VLAN membership.
This is a very brief (and non-technical) explanation so, if anyone wish to give more technical detail, please do so. You can find some more information
here.