encription oddity

[pontiend]

When I got vigin broadband,they gave me a new wireless router.I have set this up with wpa-psk encription.And mac number access.
My old router was wep enabled.My eeepc 1000he connects ok.My packard bell laptop has my old netgear wg511 buscard in it.my compac desktop has a belkin 54 card in it.
The belkin card must be at least ten years old.
The netgear and belkin adapters are both wep enabled,but both connect to the net through the router.How?.What is the point of the router being wpa enabled if it lets wep cards connect through it.Obviously when I am using the compac,as I am now, my connection is only wep enabled.
What I don't understand though is why the router allows the wep cards to connect. Any ideas.

[elli5on]

The only way you should be able to do that is by creating 2 seperate VLAN's. One using WEP and obviously the other using WPA, WEP can only talk to WEP and the same applies vice versa. The only way i can think is you must have somehow created 2 logical network's through your router for each device to connect through.

Regards