normally，there is no way to change Message Center number (SMS) .this is set by the ISP

You can try check and configure the wireless security on the tplink adapter first: http://www.tp-link.com/en/article/?faqid=398

You tablet does not have wifi function? as far as I know, the network adapter is designed to be used in the computer. maybe you can contact the tp-link or the tablet for technical advice.

maybe you can also try to draw a simple topology about the devices and network connection.

1 You can try to set the DDNS. And Peer Gateway, you can enter the domain name instead of the WAN IP 2 I am a little confused. so it is: PCs->842N(VPN server) ---internet---- Company (VPN...

B the whole powerline network rate will be 200Mbps