they are compatible. Each powerline extender can be set a different ssid, so it's fine.

it is posting:D

sadly, they don't sell one individually:( I guess you can get different models. Or get a kit:)

looks bricked to me. I guess you can try few times re-upload version 2 firmware through tftp.

I don't think you can change it from strict to open. If your SIM card provider provides you a public IP address and public gateway, I guess you can open port or DMZ for your device. Otherwise, the...

1. You'd better try a different software to scan the channel...like inSSIDer 2. the C20 is working on router mode or access point mode? is the "allow guests to access local network" checked or not?...