What's the difference between a modem and a router? Can I replace a DSL modem with a router?

I’ve got DSL through Verizon, and I’ve had the current modem (which I got from Verizon also) for several years. A regular phone line comes out of the wall, plugs into a standard phone jack in the back of the modem, and there are Ethernet jacks that our desktop computers plug into, and an antenna that allows our laptops, tablets, etc. hook up to the Web.

Lately the modem’s frequently been getting slow, then dropping the connection and needing reboot (turning it off, letting it cool down, turning it back on again, and waiting until the DSL light is steady). So we’ve been thinking that we may need a replacement.

So when a seemingly good deal for a router popped up on Woot! the other day, it made me wonder: are a router and a modem just different words for the same thing? Or do they do different things, and if so, how are they different?

I looked up ‘router’ on Wikipedia before coming here, and it’s got a pic of the back of a reasonably contemporary router that looks pretty much like the back of my modem: the phone jack, the Ethernet jacks, a plug for the power source. Sure looks like the same deal.

OTOH, my search of old threads in this forum about modems and routers all seem to talk about plugging one’s router into one’s modem. Hence the desire for clarification.

Thanks in advance for helping me fight my own ignorance.

What you have is a combination router / dsl modem. Both functions in the same package. You can buy such things off the shelf, but you should probably check with Verizon if they will work with your connection.

Strictly speaking, a router is not automatically also a DSL modem.

No, they are different things. A modem is a device that modules and demodulates digital signals onto some communications medium. Examples would be DSL modems, cable modems, and good old-fashioned POTS dialup modems.

A router (more specifically, an Ethernet router and/or wireless Ethernet router) is a device that does network-level routing between multiple devices on a network.

What you have is a combination DSL modem/Ethernet/Wireless router, provided by Verizon.

You can not replace this with a router since a router by itself does not contain a DSL modem.

You can buy third-party DSL modems, but they may not work on Verizon’s network. You’ll have to check with them. In general, you have the right to run your own equipment on telco networks, as long as it’s compatible, but you may need to still pay Verizon to rent the modem you’re no longer using. On the other hand, you may be able to return it to them and save a few bucks in your bill.

You usually rent a modem from your ISP for a small monthly fee. You can also purchase one yourself, you just have to make sure it is compliant with your ISP’s service. You have to return the one they left at your house, and also have to tell them the MAC address of the new modem so they can confirm they are sending their signal to the right place.

A router takes the signal from the modem and routes it to different devices in your home. Most residential routers nowadays are wireless and wired, with ports to plug in and antennas to broadcast.

A router is not a modem, a modem is not a router. In very basic terms you can’t plug your router into the wire coming from the wall (that’s where a modem goes) and you can’t split up your internet connection into a bunch of different connections for different devices with a modem (that’s what a router does).

Some ISPs have you rent a router + modem, which is what you have. There is a modem in there that does modem stuff, and also a router which does router stuff. It’s like a TV/VCR combo. Nice and compact but when one breaks you have to replace the whole thing.

If you now have a router, you can return your modem + router and get just a modem on rent. Or you can return it and get a new modem + router unit (which is the nice part about renting). Or you can return it and go out and buy a modem on your own.

But no, a modem and a router are not the same thing.

OK, I think I’ve got the basic idea, then: they do different things, but mine is a combo of the two, and would have to be replaced either by a modem and a router, or a modem/router combo like the one I’ve got. A router by itself wouldn’t do anything.

Safest route is to just buy a new ‘modem’ (modem/router combo) from Verizon to replace the existing one. (FWIW, this one and its predecessor have both been purchases, not rentals; at least Verizon doesn’t play that game.)

How certain are we all that he needs to get a Verizon DSL modem? Isn’t DSL pretty much DSL, regardless of the ISP? Has Verizon balkanized the protocol?

My ISP is AT&T, and I have DSL service. AT&T has a list of a few specific makes of DSL modem that they work with. All that really seems to mean is this: When you call their customer service reps to have them walk you through the set-up, those are the only ones they have the cheat-sheets for. And unless you get really lucky, you aren’t going to get a service rep who knows anything more than how to read their cheat-sheets to you.

I happened to get a combined DSL modem / router that wasn’t on their list. I also happened to get my hands on a simple modem-only that was on their list. In order to get set up, I had to install the “approved” DSL modem. Only then was the service rep able to walk me through the set-up.

The modem/router, being both and being very featureful, had many many more set-up screens and configuration options and stuff and a lot of things were labeled differently. After I got the little modem-only set up, I then connected up the modem/router and configure all the settings there the same way.

So would that work for Verizon too? Or does Verizon really only work with their own modem? I would never use an ISP that pulled a stunt like that.

In Britain virtually all home broadband networks use the combined modem/router machine. The ISP supplies this ( usually saying one is saving £90 !!! ), but does not charge rent. It is adequate if not sturdy nor state-of-the-art

[ Sadly, unless one has cable etc., broadband is tied to the landline, and one does have to pay a monthly telephone line rental, even if one doesn’t use the phone. ]
One can use one’s own modem/router with any ISP, simply by putting in the email address they give and the password, and adjusting any configuring if one needs for fine-tuning. But the spare ISP modem/router is then put in a corner, since at least with Orange, my ISP, it is hardwired only to work with Orange.
And if one has a really good expensive modem/router such as a Billion or a Fritz!Box, one is disinclined to use the ISP’s inferior model.