First issue is to make sure you can have both nic cards active at the
same time. Windows and/or the bios sometime tries to prevent you from
having both active. You need to use different SSID and channels.
Sounds like you may have that part working.
You want to run the networks on 2 different subnets. ie you want something like 192.168.1.xx on one interface and 192.168.2.xx on the other.
The next thing to do it to use a static ip address on the business network. Do not set the DNS or default gateway.
When you use DHCP from the router it gets default route from both gateways and gets confused.
In the simple case this may be all you need to do. If you have multiple subnets in the business network you will need to add routes with the route command.
If you open a command prompt and issue the command ROUTE PRINT you should see both interface and the IPs.
This list is what controls which interface the PC uses. The route command has many option that you can use to modify and I will recommend you read the documentation on microsoft site on how to use this command.
I'm helping my father with his setup at his rural small business. Internet is only available via an ATT MiFi hot spot. He currently has the business computers networked together and running accounting/point of sale software.
I just upgraded his personal computer. It has an internal wireless card and we have a USB wireless adapter installed.
What is the proper way to configure one adapter to connect to the network (via the existing linksys router) and the other adapter to connect to the ATT Hotspot? The goal being able to access the internet from the PC while still being connected to the network. Not interested in sharing the internet connection across the network or anything.
It works sometimes, but establishing and maintaining a working connection to both simultaneously is not consistent. From the internet research I've done, it seems like there can be issue with the IP addresses, but I can't find a tutorial for my exact situation.
I'm working with a Windows 7 PC.