Technical, Technology, Testimonials

SAQ: Is a DSL Modem Actually a Modem?

This question came to mind the other day. “DSL modem” sounds dumb, because as any geek over the age of 30 knows, a “modem” is a device with MODulates and DEmodulates a digital signal over an analog network. Thus a “Digital Subscriber Line” has no need for modulating and demodulating.

modem and phone

THIS is a modem!
CC: BryanAlexander

Except, DSL is actually an overlay on the analog telephone network. So, wait . . . what?

Wikipedia wastes its time on a pointless distinction:

“The term DSL modem is technically used to describe a modem which connects to a single computer, through a USB port or is installed in a computer PCI slot. The more common DSL router which combines the function of a DSL modem and a home router, is a standalone device which can be connected to multiple computers …”

Yeah, really helpful. But as geeks know, you need to check the Wikipedia talk page:

The usage “DSL Modem” is not erroneous. A DSL modem does indeed perform modulation and demodulation. It uses either Quadrature Amplitude Modulation (QAM) or Phase Shift Keying (PSK) modulation. Multiple modulated subcarriers are then combined into an OFDM stream. The distinction between this type of modem and a traditional one is that the traditional one modulates audio frequency signals whereas the DSL modem is upconverted to an RF band. But they both perform modulation and demodulation. The digital signals are not sent as baseband digital signals.

I do not know what all those words mean, but I read that as “a DSL modem is still a modem. It modulates and demodulates a digital signal into the RF band of a telephone line.”

I made my own contribution to Wikipedia’s Talk page:

The distinction between whether your “DSL modem” connects via USB, ethernet, wireless, or provides NAT, sounds like a spurious distinction to me. I interpret and interchange “DSL modem” and “DSL router” as “the network device that bridges your local computing resources to your network service provider.”

But if I have learned anything about nomenclature disputes on Wikipedia, it is that they are not worth the effort.

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Categories: Technical, Technology, Testimonials