Talk:DSL modem

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From http://electronics.howstuffworks.com/vdsl.htm: 'Most residential customers call their DSL transceiver a DSL modem. The engineers at the telephone company or ISP call it an ATU-R, which stands for ADSL Transceiver Unit - Remote.' I'll leave it up to wiser heads than me to figure out what to make of this. 2006-05-19 03:30 UTC

The common usage "DSL Modem" is erroneous, oxymoronic, and frankly quite silly to anyone who actually knows what a modem is. The word modem is a contraction for MOdulator/DEModulator. Modulation is the process of converting a digital signal onto an analog carrier, and demodulation is the process of converting a modulated signal back to its original digital form. In an all-digital technology like ADSL, there are no analog signals and therefore there is nothing to modulate or demodulate. However, because ADSL Transceivers perform the same approximate function as an analog modem (serving as the intermediary between local computer equipment and the telephone network), the public at large seems insistent on incorrectly applying the word "modem" to this piece of equipment that is anything but a modem. 2006-09-03 04:20 UTC

Technically correct, but I guess you could say that the word "modem" originated from the name "modulator/demodulator", but now it is a generic word for a consumer device used to connect a computer to a telecommunications network. Maybe "ADSL router" would be a better name for the article, but not all ADSL modems have router functionality. -- Chuq 12:12, 4 September 2006 (UTC)

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.

Our unsigned colleague is correct. The colloquial usage "DSL Modem" should be applied, because it is both widespread and technically correct. It modulates; it demodulates; it does all that a modem should do. It does not dial a phone number, and it does not limit its analog signal to one that can be carried by a loaded telephone cable or a ds0 channel. Those characteristics are commonplace, but they have never been part of the definition. As seen in the Modem article, a "modem" does not have to be voiceband limited. Voiceband, dial-up modems were merely the most common late 20th Century kind; they are not the technical or colloquial definition of "modem." Thus the name of the article should be restored to "DSL Modem."

Jim.henderson 15:02, 29 October 2006 (UTC)

[edit] Broadband modem never in add-in card format?

Its curious that broadband modems are never add-in cards - dial-up cards are ubiquitous. I assume they exist but I cannot find even one. Is there a technical reason for this or is it just that the market prefers external boxes?--ChrisJMoor 19:30, 31 March 2007 (UTC)

I think some internal ones were sold around the turn of the century but were discontinued for reasons of versatility and diversity. First, not every DSL modem works with every line; to be sure you have to use the one that your telco provides for your line. Second, not every DSL line has only one computer. I think the companies should have handled this better, allowing multiple modems to share a phone line and all compatible so the modem could be an internal part of the computer and not require the wall wart and Ethernet cable that add to the opportunities for consumers to install wrong. Now it's probably too late to use these advantages against the CATV companies. Jim.henderson 04:50, 6 April 2007 (UTC)

Overall, there are advantages to the 'one external box' package over the add-in card, for the reasons you state above. However, I cannot understand why there is a complete lack of broadband cards these days and I cannot find any information addressing this. If you or anyone else can get this info, add it to the article!

By the way, you mention CATV companies (cable TV I assume). I don't quite understand your point there.--ChrisJMoor 00:00, 12 April 2007 (UTC)

Drat, what happened to my text? Must have hit the wrong key with the arm that's impaired by a broken collarbone. Anyway, the problem is diversity and lack of versatility in ways to provide high speed Internet. CAble TV Internet services are not compatible to DSL hardware and vice versa, and not always compatible to each other's hardware. DSL hardware is also not always compible. These several ways to bring Internet home mean, if the computer came with built in DSL hardware, it wouldn't work in some places, so the consumer would bring the computer back to the store whining that it's broken. Had the phone companies understood the future, they could have made DSL cards compatible to each other and more versatile, for example able to connect multiple computers to the same DSL line. Then the same modem card in each computer could provide both voiceband and wideband service behind the same RJ-11 socket. That would make Ethernet unnecessary at home, with no external equipment to buy or plug in. Such simplicity and versatility couldn't be matched by a CATV connection that requires a converter box anyway. Ah well, it's all in the realm of "if" and far too late. Jim.henderson 00:29, 16 April 2007 (UTC)

• Analog modem usually built-in?

I doubt that "voiceband modems are usually built inside the computer." While internal voiceband modems are more widespread than internal DSL modems, in my experience the (vast) majority of analog modems are external devices. Be it as it may, this is certainly not a distinguishing technical feature, but merely a marketing decision. —Preceding unsigned comment added by Grissom (talk • contribs) 12:20, 7 May 2008 (UTC)

Eh? In my BBS operator days I used external modems, but my callers almost all used internal ones. Look at the computer shelf of any consumer electronics shop in the past decade, and almost all have an internal voiceband modem. Voiceband modems sold separately are still sometimes external ones, but most are offered as computer parts inside the case, same as the Ethernet and video ports, rather than as accessories as monitors and mice are. Yes, it's a marketing decision and not completely uniform, but it is usual. Jim.henderson (talk) 03:48, 13 May 2008 (UTC)

[edit] Requested move

I am requesting this page be moved back to "DSL modem." This is by far the common name for this device. The article uses the term "DSL modem" except for the introduction. The discussion above does not seem to support the move that was made, yet it happened anyway. it should be moved back.--agr 22:39, 4 June 2007 (UTC)

Yes. "DSL modem" is (1) term by which most users call it, (2) more precise than "transceiver", and (3) technically correct. Jim.henderson 16:26, 6 June 2007 (UTC)

No, it isn't more correct, Modems are for analog to digital (and vice versa) connections, and CSU/DSU's or transceivers are for digital to digital. Mobus 00:52, 14 July 2007 (UTC)

In what sense is the phone line signal of some other gadget "analog", and the phone line signal of the present gadget not "analog"? Jim.henderson 00:57, 18 July 2007 (UTC)

This article has been renamed from ADSL transceiver to DSL modem as the result of a move request. --Stemonitis 08:41, 10 June 2007 (UTC)