I was going through the settings in the Network Setting Mode on the IP phone (IPT2020). What are the purposes of the following settings?

1. Default Router Address - This is typically assigned by DHCP or should I put one in? Should this be the IP address of the linksys/netgear router?

2. Admin IP Address Lower/Upper - ?

3. PASSWORD(Within 16char) - Can I assign a password at the PBX level so only phones with the correct password can connect?