Do they make a modem splitter to hook up my wireless router

a PC modem like in a Dial-up Modem?

It is a cable modem supplied from Armstrong Cable

What I did was take the what looks like a ethernet cable out of the modem and plugged in the wireless netgear router into that spot. Then I plugged in what looks like the ethernet cable into the netgear router. trying to get both the wireless internet and the cable internet to my PC. I get wireless internet but no PC internert. So I was thinking if there was a splitter to go into the modem I could then hook up both ( wireless and cable internet to the PC). I hope this makes sense.

if the wireless internet is via a cellphone provider and you are trying to connect the internet via Cable at the same time, too, it will not work.

Windows will only use one internet connection at a time. the OS does not support load balancing between two connections and it will not do an automated connection fall back (when one connection fail the other will activate) either.

I see what your saying and it makes sense. My internet supplier is thru my cable co. I tried to use the internet connections with my IPad and PC and it didn't work. Then I tried one at a time. The IPad always found a internetconnection and the never did. I am just looking to use one or the other it would be nice to have both at the same time would be great in case someone needed wireless when the PC is online..