Broadband v. baseband ... again?

Broadband isn't a speed, it's a signaling architecture. The alternative is
baseband. Ethernet is baseband. Broadcast radio is broadband. Now that you
have the two competing terms, please see your friendly neighborhood search
engine (PSYFNSE).

BTW, silence is a poor excuse for posting a message.

Though, to be fair, a lot of people have coopted the term "broadband." You
and I know that broadband is defined in the 802 series of specs as a way
to run ethernet over an analog cable system. But... the cable companies
would have you believe that it means "the fastest thing going" and the
telcos would have you believe that DSL is "broadband."


If you want to get to the root of these terms, without getting caught up
in all of the ways their meaning has been distorted, the best place to look
may be a dictionary.

In baseband signalling, you have one signal using all of the bandwidth
available on the wire. In broadband signalling, there are multiple signals
on the wire, multiplexed in the frequency domain.

At the risk of incurring the wrath of Mr. Meyer by posting without permission, I offer the following: Harry Newton, of "Newton's TELECOM Dictionary - The Official Dictionary of Telecommunications & the Interent" (Updated 15th Expanded Edition), defines "Broadband" (in the WAN context) as anything over 45Mbps (T3).

The language we use in our industry is evolving at an extremely rapid rate. The great unwashed masses don't necessarily stick with the time honored definitions we would prefer that they admire, respect, and accept as gospel. Get over it!

    - Tom

...and by and large, they'd be right. Most DSL shares the same wire with
voice, at a different frequency.


Interesting enough:



A type of data transmission in which a single medium (wire) can carry
several channels at once. Cable TV, for example, uses broadband
transmission. In contrast, baseband transmission allows only one signal at a

Most communications between computers, including the majority of local-area
networks, use baseband communications. An exception is B-ISDN networks,
which employ broadband transmission.


The original band of frequencies of a signal before it is modulated for
transmission at a higher frequency. The signal is typically multiplexed and
sent on a carrier with other signals at the same time.

(TechEncyclopedia by Techweb)


(1) High-speed transmission. The term is commonly used to refer to
communications lines or services at T1 rates (1.544 Mbps) and above.
However, the actual threshold of broadband is very subjective and may be
well below or well above T1 depending on the situation. For example,
(see TrueMotion) offers "broadband streaming video" to users with access to
the Internet at 250 Kbps or higher. Other sources claim 45 Mbps is the
starting point. In every case however, it implies transmitting at higher
speeds than what has been most common up to the current time. See cable
modem, DSL and T1.

(2) A method of transmitting data, voice and video using frequency division
multiplexing (FDM), such as used with cable TV. Modems are required to
modulate digital data streams onto the line. Broadband in this context is
used in contrast with baseband, which is all digital transmission and uses
time division multiplexing (TDM). However, the term is mostly used in
definition #1 above. See baseband for illustration.