Linksys Router / ATA 186 DHCP issue

My building has T1 service with DHCP.

I use a Linksys wireless router which is connected to the ATA 186.

When my ISP swaps out the IP, the ATA goes down.

It sounds like I need to give the ATA a static ip and do some forwarding in my routers settings.

Is this correct? I use Iconnecthere service, and it is flawless when the everything is communicating.

Can anyone help?

Thank you