Here's the situation:

I've got Cox Digital Cable/Internet using a Motorola SBV52222 Modem and until recently, I only had my laptop hooked up via an ethernet cable and everything worked fine. Yesterday I added a PS3 to my setup and attempted to connect it to the modem. Being that the modem only has 1 ethernet port, I simply removed the ethernet cable which runs to my laptop and plugged in an ethernet cable that leads to my PS3. Long story short, the PS3 would not connect, as it was unable to even attain an IP address. After several conversations with both Sony and Cox tech support, I was able to get it connected by resetting the modem. However, when unplugging the PS3 ethernet and reconnecting the laptop, again, no internet connection until I once again reset the modem. The Cox tech support said if I purchase a switch then it would solve this problem. So I did just that, and I'm running into the same issue: the modem will only connect to one device at a time. It tends to prioritize the connection to the laptop instead of the PS3, but like I said it will not connect to both simultaneously. All the connectivity lights on the switch are illuminated indicating that all devices are receiving connection. I'm not sure if the PS3 and laptop use different "connection types" or what but I've never encountered this problem before. It's always been simple as plug and play. Do I require a router to get connection to both devices simultaneously?

Thanks in advance for any responses.