VoIP- Switch or Router?

[jsnap]

I'm presently using a D-Link DSS-5+ switch so I can get VoIP phone service over my cable internet connection. I'm using a Motorola SB4200 cable modem, a Cisco ATA 186 Analog telephone adapter, running OSX 10.2.8 on my G4 Powermac. The cable service (from Comcast) comes in to the modem, then goes to the D-Link switch, then to both the computer and the Cisco device. I keep loosing my phone connection when the internet goes down. So far, I can get an IP for both services, but I can't a dial tone again from Vonage (the VoIP phone service). Vonage tells me I need to use a router, not a switch. Is this correct?
If yes, got a suggestion on a reliable router?

 

[ElDiabloConCaca]

If the VoIP device needs its own IP address, then yes, you do need a router. Just like if you were to hook up two computers to use the same cable modem, you'd need a router to provide IP addresses to the two computers... not a switch, which won't do that.

 

[jsnap]

Turns out when I lost phone service, what really happened was I lost my cable internet. It happened when I was gone for a few hours, only my kids didn't tell me this. They rebooted the computer but not the Cisco ATA telephone adapter (which they know nothing about). Today, I finally got someone at Vonage (the VoIP provider) who understood using a switch as opposed to a router. What I needed to do was to reboot the Cisco phone adapter first so it gets an IP address from the cable company before they see the computer.

As for using a router, this will solve my issue more readily and allow me to share the internet with my daughter's iBook. Now all I need is the right router and a printer that will support a wireless printer server.