What is an Ethernet Modem?

Douglas Bonderud

An Ethernet modem is an electronic device used to connect a computer to the Internet. This sort of modem uses broadband technology to transfer and exchange data packets in real time. It usually comes in one of two forms. Ethernet-enabled digital subscriber line (DSL) modems use phone lines, whereas cable modems use designated cable lines, usually the same ones that subscribers use for television services. They work in the same way, at least from a technical perspective, and both are known as “Ethernet” because of the way they are wired. Universal serial bus (USB) modems are similar, but distinct largely in terms of the cabling they use for data porting.

Ethernet modems are used to connect computers to the Internet.
Ethernet modems are used to connect computers to the Internet.

Basic Operation

All Ethernet modems feature at least three connections. One is for a power source, typically an alternating current (AC) wall socket. The second is for the Ethernet cable itself, which runs from the modem to a computer's network interface card (NIC). Third, there is a connection for either a phone or digital cable cord, which is usually hooked up to a wall jack.

An ethernet cable.
An ethernet cable.

There are also modems that can send and receive signals wirelessly. This usually happens with a special adapter or wireless router that transmits the modem’s signal to the immediate vicinity. People can pick up this signal with devices that have a wireless card or other networking capabilities, and these devices don’t usually need a separate modem. The fact remains that the Internet connection must have a modem at its source, though, even if it’s only connected to a network server or wall socket.

A network interface card, which connects to an Ethernet cable.
A network interface card, which connects to an Ethernet cable.

Distinguishing the Two Main Types

Modems that are classed as Ethernet usually come as either DSL or cable. A DSL modem connects to the Internet via a phone line, but uses frequencies at the upper range of the line's capabilities, beyond those used for sound transmission. This means that people can generally use their phones at the same time as they’re online. Cable modems connect to the Internet by using the same digital cable lines that televisions use to receive programming. Again, the portion of the line that’s used for Internet transmission is different than that used for cable, so customers can be watching television while also using the Internet. Many digital cable providers actually use the Internet to transmit and store broadcasts, too.

Ethernet cables plugged into an Internet switch.
Ethernet cables plugged into an Internet switch.

Origins and Name History

The term Ethernet is a reference to the passive substance ether, which was once thought to pervade all things. In theory, ether carried light throughout the universe. In the context of the Internet, Ethernet uses the passive medium of cables to transmit data throughout its network. The first modem of this type was created in the 1970s by American computer scientist Robert Metcalfe, and was based on an earlier system of Internet connectivity known as Alohanet. Ethernet originally had theoretical data transfer rates of up to ten megabits per second (Mbps). Current technology allows for much faster speeds.

Comparison to USB Modems

Ethernet tends to be one of the most widely used cable modems, though it does get some competition from USB modems. Both operate in a similar fashion and have similar data transfer speeds, although Ethernet is usually considered to be more reliable in the long term. The biggest difference is often the cabling and the fundamentals of the porting and wiring systems.

The cable jacks used by an Ethernet modem closely resemble those of a phone cord. They are slightly wider, however, and the cable itself is also thicker. USB cables, meanwhile, have a flat metal connector that plugs into the USB ports found on desktop computers. The advantage of Ethernet cable over USB is that Ethernet cables can reach up to 328 ft (100 m) with no degradation in signal. USB cables are typically limited to 16 ft (5 m).

USB modems have advantages, too, though. One of the biggest is that this sort of modem can connect to any computer that has a USB port. An Ethernet modem requires an Ethernet network adapter in the computer. This can mean a higher initial cost, and can also be more limiting in terms of hardware compatibility.

One of the jacks on an Ethernet modem will connect an Ethernet cable to a computer's network adapter.
One of the jacks on an Ethernet modem will connect an Ethernet cable to a computer's network adapter.

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Discussion Comments


@JimmyT - In my experience, getting the wireless modems isn't worth it unless you absolutely have to have an internet connection in places where there is no other way to get access.

My sister had a card like that through her wireless provider that let her get internet, because she traveled a lot. She has always been afraid of using airport connections and thought the Ethernet modem card might be easier. What you are really getting, though, is just cell phone internet on a laptop. When you consider how slow most 3G connections are, you can imagine that you can't be very productive.

Even with 4G, I still don't think you'll have the same capabilities as with regular WiFi connections. I would say to just risk the WiFi unless you absolutely need the wireless card.


@kentuckycat - I have never heard of a wireless modem that was able to be used as the main modem for a house. I don't think any cable providers offer wireless internet access, either.

I assume what the article was referring to was using USB-based cards that plug into a computer. Something like a 3G Ethernet modem offered by a cellular company that allows you to get internet access using cell phone networks.

Depending on the provider, they may work differently. Any of the modems I have seen plug into the media slot on a computer and allow connections that way. The article mentions being able to connect through USB, and I have heard of those being available, as well. I have never used a wireless modem, so I don't know how well they work, though.


@cardsfan27 - From what I had been told, a lot of people say that cable modems are generally faster than DSL, but I don't know whether it is really true in practice. I have had both kinds of modem, and I think the difference in speeds, if any, is imperceptible. I think a lot of it really just comes down to your provider and what services they offer.

What I don't know about is how well the wireless Ethernet modems work. I was not even aware that wireless technology existed yet. I know with all things, wireless goes a little bit slower than the wired counterpart, but I don't know if it has any noticeable effect. How would the wireless modems work, though? I have not heard of any companies using them. Where does the signal come from, and what stops people from being able to steal the connection?


I never realized how much went into being able to use the internet every day. I guess we really take for granted all of the stuff happening behind the scenes when we start up our computers. I still remember the days of 56k modems and having to sit through the dial-up process. Even after all of that, the internet stilled crawled along compared to broadband, which is basically an instant connection. I always like telling younger people how good they have it not having to wait for dial-up.

I had heard the term DSL used a lot, but I was always under the impression that it was the same as cable internet. I guess that isn't the case, though. Is there any real difference in quality between the ethernet cable modems and DSL modems?

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