|I suspect wizard-fred is correct and you previously had a combination unit. We usually refer to them as just a "combo" unit.|
A combo unit is a modem, a SOHO (small office/home office) router, and a wireless access point all in one device.
If that is what you had with your previous provider, you will want to buy a SOHO router to put between your modem and your switch.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.