Connecting IP Phone to modem

[semiarid]

Hi,

Do I need a router between an IP Phone and a modem?

I have been using VoIP.ms quite successfully at home by connecting my existing PSTN phones to my SPA2102, (assigned one IP address) then to my HP Procurve switch and on to my Shaw modem. My home computer internet is serviced from a E4200 Tomato RAF router (assigned a second IP address) which is also connected to the switch. Throttling and QoS on the Tomato allows for sufficient headroom for the SPA2102 and softphones.

Now that I am switching to IP Phones (Panasonic KX-TPG550 and KX-TPA50's), I was wondering if there is any risk in connecting the KX-TGP550 to the switch and on to the modem without a router between the phone and switch. Is a router necessary for security?

I have a spare E3000 with Tomato loaded (and of course the SPA2102) to connect the KX-TGP550 to if a router is required for security, but can I keep it safe and simple and avoid NAT hassles by exposing the IP Phone to a public address assigned by Shaw?

Thanks,
Greg