What is an Ethernet Modem?

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.

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.

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.

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.

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.

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.