Using all 4 Ports

[NightFlyer80]

please note my CM1200 is not a router, just a modem.

I bought this modem with the intention to use 3 of the 4 LAN ports at once. I have since been told that this is not possible with a modem. This has also been my experience, when my router is plugged in, i cannot hard wire my computer to the modem.

can someone please confirm that I will not be able to plug in 3 devices at once to this modem? i want to have a router, a TV and an apple
tv all plugged in via ethernet at one time.

[plemans]

For the majority of ISP's only 1 device can be connected to the CM1200 on a consumer grade plan. 

Business class lines or people on consumer plans who pay for extra IP address can use more. Most people don't. 

Who's your ISP?

[antinode]

> can someone please confirm [...]

   You might try an oft-neglected resource:

      https://en.wikipedia.org/wiki/RTFM

   Visit http://netgear.com/support , put in your model number, and look
for Documentation.  Get the User Manual (at least).  Read.  Look for
"Ethernet port"?

      https://community.netgear.com/t5/x/x/m-p/1770096

   It's conceivable that your ISP could provide you with service which
would allow multiple external addresses, hence multiple devices directly
connected to the CM1200, but exposing your computers/devices directly to
the Internet (that is, without a NAT router in between) would probably

be a big mistake.

[NightFlyer80]

I have Cox internet at my house. We have the gigablast plan.

[NightFlyer80]

can I use a switch with this modem to get more devices connected to it?

[antinode]

> can I use a switch with this modem to get more devices connected to
> it?

   No.  If your ISP gives you one external IP address, which would be
typical, then you need to connect a NAT router, ONLY, to your modem.
Your client devices would be connected to that router.

   The problem with the modem is not a shortage of ports, it's a
shortage of brains, which is what the NAT router provides.

[NightFlyer80]

Thank you.