What Is the Difference Between Cable Modem & DSL Networking?

A stack of broadband modems.

There are many differences between Digital Subscriber Line (DSL) networking and cable modem Internet service. In fact, the only real similarity is that they are both considered always-on high speed, or broadband, in terms of access speed. DSL connects through the same home phone line that voice connections do, using a lower frequency than typical voice communications to maintain its broadband speeds. Cable connects through an established cable television connection. There are limitations and advantages for each.

Availability

One major limitation of DSL is that, in order to establish service, a subscriber must be within approximately 18,000 feet (about three miles) of a central office (CO), as DSL signal strength fades over distance, making connections slower the farther from the CO a subscriber gets. Cable does not share the same disadvantage and is available to anyone with cable service.

Connectivity

Both DSL and cable are always-on connections, meaning no dialing or otherwise establishing of a connection is necessary. However, they do work a little differently when it comes to sharing the connection.

DSL does not share its bandwidth throughout a line, so its speed should be more reliable than cable, which must share a connection with other subscribers on a network. This means that cable will usually slow down during peak hours.

Bandwidth

In terms of raw speed capability or bandwidth, cable takes the prize with a basic access speed of 4 to 6 Mbps and a premium access speed of 20 Mbps or more. DSL is limited to a range between 768 Kbps for basic service and a maximum of 7 Mbps for premium access.

In general, cable is considered faster than DSL, despite its disadvantage of slowing down at peak hours.

Cost

DSL has the advantage in terms of cost; plans usually range from about $20 a month for basic access up to $45 or so for premium access. Cable usually costs at least $40 a month for basic access and may scale up to $55 or more for premium service.

Latency

In terms of latency, the amount of time it takes to send and receive a single packet of data, DSL has the advantage over cable. This means it is slightly better for time-sensitive applications like video conferencing, VoIP, online gaming and other real-time applications.

Security

Because DSL isn't shared between subscribers, it is considered to be somewhat more secure than cable.

References

• High Speed Internet: DSL Internet vs Cable Internet
• James Thornton: Cable vs. DSL: Latency
• Geek Squad: Cable vs DSL Internet Connections