USR-IO424T-EWR - 4-way network IO controller

Question:

1. How to buy 4-way network IO controller USR-IO424T-EWR - , how to pay? 

2. If one connects to the USR via Web-Browser, can one simply switch any or all of the 4 relais outputs? (the manual isn´t clear to me with regard to this point)
3. Which port is the USR using? I am asking this because I want to get access from remote using port forwarding in my router, not using any cloud-solution.
4. The relais-output is potential-free, NC/N0?
 

Answer:

1.you can buy IO Controller  from our official shop: https://en.usr.cn

2.yes, they can
RS485:RS485 interface, A, B, G interface, only AB can also communicate.
DO:DO1~DO4 is the output of 4 channels and DO-COM is the public end.
DI: dry contact input, DI-COM is public end.

3.IO424 connects PC through USB to 485, and connects the router through the network cable.You can connect to your own server.

4.NC