Connecting Two Computers To A Single Cable Modem

I'd like to connect my new laptop to the same cable modem as my mid-tower PC, without having to constantly swap the Ethernet connectors to the modem--if that is possible...

The PC and the laptop will not be in simultaneous use!

Is a router required for such a setup?

Can some kind of switch-box handle that?

Running under Windows 7 Pro, soon to be Windows 10 Pro.

 

most cable modems that i have seen have more than one ethernet port in the back. if so, just get another ethernet cable, plug it in the back of the modem in an unused port, connect to laptop, and you're good to go. if there is only one ethernet port on the modem, just buy a hub/switch ( 3 or 4 or 5 port )( any brand ) the cable modem goes to the hub/switch and the 2 computers connect to the hub/switch. at one time, there was a difference between hubs and switches, hubs were "dumb" ie: no built in intelligence, switches look identical to hubs, but have intelligence built in to them. for your situation, either one would work.
actually, a thought just occurred to me. most all cable modems, now a days, have wireless capabilities. and, i imagine, most laptops have wireless capabilities. so you could just connect to the cable modem wirelessly. some where on the cable modem should be a sticker. on the sticker will be the name of its wireless network name and the passcode needed to connect to it. i imagine that if you turned on the laptop without a cable plugged in, it will search for wireless networks to join. it would find yours [ and all of your neighbors ] just select yours, enter the passcode, and that's all there should be to it. i dislike wireless connections, so i never think of it initially. anyway, good luck with it.

 

I agree with harmless.
My PC is connected to a mobile modem via USB cable, and the mobile phone connects via Wi-Fi to the modem.
Up to 10 devices can connect to the modem.

 

Sorry, but that is not true. Some modems do, but "most" do not.

What is needed is a router with a 4-port Ethernet switch (and the vast majority of home routers include a 4-port switch).

By definition, a modem does NOT have more than one input and one output. If it does, then that is an "integrated" network device that is typically "marketed" as a "Residential Gateway" device. An residential gateway device integrates a modem, router, 4-port Ethernet switch, and typically a WAP (wireless access point) into one box. These are 4 discrete network devices that just happen to share a printed circuit board (PCB), case and power supply. Some may even include VoIP (voice over IP). A fifth discrete device integrated into the same box that adds Internet phone service to your network.

You will often here the term "wireless router". Technically, there is no such thing! All routers are wired, with just one input and one output. A "wireless router" is a "marketing" term for an integrated device that includes a router, WAP and 4-port Ethernet switch. Three discrete network devices that again, just happen to share a common PCB, case and power supply.

The most common setup these days is a wireless router connected to a separate cable or ADSL modem. If you buy your own network devices, this is the setup I recommend. If you rent the network device from your ISP, you most likely will get a single integrated device, a "residential gateway". I don't normally recommend renting because they end up costing more in the long run.

So, to clarify a bit:

1. A router connects (or isolates) two networks - typically the local or home network and the Internet.
2. An Ethernet switch allows connecting 4 or more wired devices to the local side of the router.
3. A wireless access point allows wireless devices to connect to the local side of the router.
4. A modem acts as the "gateway" device connecting the local area network to the ISP's network.​

Again, 4 discrete devices that may or may not share a common case. Five devices if VoIP is included.

Yes, and it is very easy too. But it should be pointed out that putting a router between your computers and your modem also adds a HUGE layer of security to your network (everything on your side of the modem). This is a VERY GOOD thing!

What happens is the router will assume the IP address assigned by your ISP and then your router will assign new IP addresses to each of your connected devices. Technically you can add 254 devices, if you want!

You can get a basic Ethernet only router, but I would recommend you get a wireless router, even if you currently don't have any wireless devices. You can easily disable the wireless side for now. Plus, wireless routers have become so popular, they are often even less expensive than wired only version. And remember, wireless routers still have an integrated 4-port Ethernet switch.

Also, many smart phones will connect via wifi if a wireless network is available (and you configure the cell phone to use it). Many users prefer this because that data does not count against your cell minutes.

Another great advantage for having a router is you can network your printer. This lets you put the printer anywhere in the house where there is network access, and anybody/computer on your network can print to it. The printer does not have to be tethered to any computer and no "host" computer has to be up and running to let the other computers print. And more importantly, no host computer has to have "sharing" enabled which creates a new set of security risks.

Typically to add a router, you simply unplug power from your current modem and computers. Don't just power down the computers because you need to remove all standby power too. Connect via Ethernet cable the router to the modem, and the computers to the router. Then plug in your modem and wait for the lights to settle down. Plug in the router and wait for those lights to settle down. Then plug in and power up computer #1. It should pick up it's new IP address and you should be able to access the Internet just as before. Only now, you are behind a brand new and powerful layer of security provided by your router!

Then connect your other computers and you should be good to go.

If you get a wireless router, enter the router's admin menu by entering its IP address in your browser. The router manual will have this information. It typically is something similar to 192.168.1.1 and the default admin user name and password are typically "admin". Change the password and passphrase to something more secure you can remember. Hopefully you use a password safe so you don't have write those down or worry about forgetting them.

Note a wireless router (or Residential Gateway device) will have both a "password" and a "passphrase". The password is the needed to access the router's admin menu. The passphrase is only for the wireless side of you network and is what every wireless device needs to access your network. Both need to be changed from the defaults and neither should be something a nosy neighbor can guess.

This all may sound complicated but it is MUCH MUCH easier than it sounds. And for sure, we are here to help.

 

Thanks!

I already do have a router--an Asus RT-N66U.

But not hooked up yet. And not wireless.

https://www.asus.com/us/Networking/RTN66U/

 

An Arris Surfboard SB6190. ISP is RCN.

 

Ummm, it is wireless. That's what those 3 antennas sticking up are for. It supports 802.11n - not the latest but good enough for most.

That's actually a nice wireless router. The antennas detach which is nice when extended range is needed.

It also has 4 10/100/1000Mbps Ethernet which is the latest - and fastest. So that is good.

So all you need is a short Ethernet cable to connect that ASUS wireless router to your Arris modem.