Can't access adminpage of the router from the 1st...

Question

Hi there I've 2 LAN 1. with the main Modem (Dlink DSL-2640T) the gateway is 192.168.1.1 2. with (Linksys WRT54GL) the gateway is 192.168.2.1My question is how i could open the (WRT54GL) page from a PC in LAN1?Many many thanks for your time.