Internet access is a form of
Internet access that uses the
facilities of the public switched telephone network (PSTN) to
establish a connection to an
Internet service provider
Internet service provider (ISP) by
dialing a telephone number on a conventional telephone line. The
user's computer or router uses an attached modem to encode and decode
information into and from audio frequency signals, respectively.
Tom Truscott and Steve Bellovin, graduate students for Duke
University, created an early predecessor to dial-up
called the USENET. The
USENET was a
UNIX based system that used a
dial-up connection to transfer data through telephone modems.
Internet has been around since the 1980s via public providers
such as NSFNET-linked universities and was first offered commercially
in July 1992 by Sprint. Despite losing ground to broadband since
the mid-2000s, dial-up may still be used where other forms are not
available or the cost is too high, such as in some rural or remote
2 Replacement by broadband
3.1 Using compression to exceed 56k
3.1.1 Compression by the ISP
3.2 List of dial-up speeds
Dial-up connections to the
Internet require no infrastructure other
than the telephone network and the modems and servers needed to make
and answer the calls. Where telephone access is widely available,
dial-up remains useful and it is often the only choice available for
rural or remote areas, where broadband installations are not prevalent
due to low population density and high infrastructure cost. Dial-up
access may also be an alternative for users on limited budgets, as it
is offered free by some ISPs, though broadband is increasingly
available at lower prices in many countries due to market competition.
Dial-up requires time to establish a telephone connection (up to
several seconds, depending on the location) and perform configuration
for protocol synchronization before data transfers can take place. In
locales with telephone connection charges, each connection incurs an
incremental cost. If calls are time-metered, the duration of the
connection incurs costs.
Dial-up access is a transient connection, because either the user, ISP
or phone company terminates the connection.
Internet service providers
will often set a limit on connection durations to allow sharing of
resources, and will disconnect the user—requiring reconnection and
the costs and delays associated with it. Technically inclined users
often find a way to disable the auto-disconnect program such that they
can remain connected for more days than one.
Pew Research Center
Pew Research Center study stated that only 10 percent of US
adults still used dial-up
Internet access. The study found that the
most common reason for retaining dial-up access was high broadband
prices. Users cited lack of infrastructure as a reason less often than
stating that they would never upgrade to broadband. According to
United States Federal Communications Commission
United States Federal Communications Commission (FCC), 6% used
dial-up in 2010. By 2013, that number had fallen to 3%.
Replacement by broadband
Broadband internet access via cable, digital subscriber line,
satellite and FTTx has been replacing dial-up access in many parts of
Broadband connections typically offer speeds of 700 kbit/s
or higher for two-thirds more than the price of dial-up on average.
In addition broadband connections are always on, thus avoiding the
need to connect and disconnect at the start and end of each session.
Finally, unlike dial-up, broadband does not require exclusive use of a
phone line and so one can access the
Internet and at the same time
make and receive voice phone calls without having a second phone line.
However, many rural areas still remain without high speed Internet
despite the eagerness of potential customers. This can be attributed
to population, location, or sometimes ISPs' lack of interest due to
little chance of profitability and high costs to build the required
infrastructure. Some dial-up ISPs have responded to the increased
competition by lowering their rates and making dial-up an attractive
option for those who merely want email access or basic web
Internet access has undergone a precipitous fall in usage, and
potentially approaches extinction as modern users turn towards
broadband. In contrast to the year 2000 when about 34% of the U.S.
population used dial-up, this dropped to 3% in 2013. Adding to the
extinction of dial-up is many newer programs such as antivirus and
major applications download their sizable updates automatically in the
background when a connection is first made and this can greatly impact
the available bandwidth available to other applications like browsers
until all updates have completed which may take several minutes or
longer. Since an "always on" broadband is the norm expected by most
newer applications being developed, this automatic upload trend in the
background is expected to continue to eat away at dial-up's available
bandwidth to the detriment of dial-up users' applications. Many
newer websites also now assume broadband speeds as the norm and when
confronted with slower dial-up speeds may drop (timeout) these slower
connections to free up communication resources. On websites that are
designed to be more dial-up friendly, use of a reverse proxy prevents
dial-ups from being dropped as often but can introduce long wait
periods for dial-up users caused by the buffering used by a reverse
proxy to bridge the different data rates.
An example handshake of a dial-up modem
"Dial up modem noises"
Typical noises of dial-up modem while a modem is establishing
connection with a local ISP-server in order to get access to the
Problems playing this file? See media help.
Modern dial-up modems typically have a maximum theoretical transfer
speed of 56 kbit/s (using the V.90 or
V.92 protocol), although in most
cases, 40–50 kbit/s is the norm. Factors such as phone line noise as
well as the quality of the modem itself play a large part in
determining connection speeds.
Some connections may be as low as 20 kbit/s in extremely noisy
environments, such as in a hotel room where the phone line is shared
with many extensions, or in a rural area, many miles from the phone
exchange. Other factors such as long loops, loading coils, pair gain,
electric fences (usually in rural locations), and digital loop
carriers can also slow connections to 20 kbit/s or lower.
[The dial-up sounds are] a choreographed sequence that allowed these
digital devices to piggyback on an analog telephone network. A phone
line carries only the small range of frequencies in which most human
conversation takes place: about three hundred to three thousand hertz.
The modem works within these [telephone network] limits in creating
sound waves to carry data across phone lines. What you're hearing is
the way 20th century technology tunneled through a 19th century
network; what you're hearing is how a network designed to send the
noises made by your muscles as they pushed around air came to transmit
anything [that can be] coded in zeroes and ones.
-Alexis Madrigal, paraphrasing Glenn Fleishman
Analog telephone lines are digitally switched and transported inside a
Digital Signal 0 once reaching the telephone company's equipment.
Digital Signal 0 is 64 kbit/s and reserves 8 kbit/s for signalling
information; therefore a 56 kbit/s connection is the highest that will
ever be possible with analog phone lines.
Dial-up connections usually have latency as high as 150 ms or even
more; this is longer than for many forms of broadband, such as cable
or DSL, but typically less than satellite connections. Longer latency
can make video conferencing and online gaming difficult, if not
impossible. An increasing amount of
Internet content such as streaming
media will not work at dial-up speeds.
Older games released from the mid-1990s to the mid-2000s such as
EverQuest, Red Faction, Warcraft 3, Final Fantasy XI, Phantasy Star
Online, Guild Wars, Unreal Tournament, Halo: Combat Evolved, Audition,
Quake 3: Arena, and Ragnarok Online, are capable of running on 56k
dial-up. The first consoles to provide
Internet connectivity, the
Dreamcast and PlayStation 2, supported dial-up as well as broadband.
GameCube had an ability to use dial-up and broadband connections,
but this was used in very few games and required a separate adapter.
The original Xbox exclusively required a broadband connection. Many
computer and video games released since the mid-2000s do not even
include the option to use dial-up. However, there are exceptions to
this, such as Vendetta Online, which can still run on a dial-up modem.
Using compression to exceed 56k
The V.42, V.42bis and
V.44 standards allow modems to accept
uncompressed data at a rate faster than the line rate. These
algorithms use data compression to achieve higher throughput.
For instance, a 53.3 kbit/s KURAC connection with
V.44 can transmit up
to 53.3 × 6 = 320 kbit/s if the offered data stream can be compressed
that much. However, the compressibility of data tends to vary
considerably, for example, due to the transfer of already-compressed
files (ZIP files, JPEG images, MP3 audio, MPEG video). A modem
might be sending compressed files at approximately 50 kbit/s,
uncompressed files at 160 kbit/s, and pure text at 320 kbit/s, or any
rate in this range.
Compression by the ISP
Main article: Web accelerator
As telephone-based internet lost popularity in the mid 2000s, some
Internet service providers such as TurboUSA, Netscape, CdotFree, and
NetZero started using data compression to increase the perceived
speed. As an example, EarthLink advertises "surf the Web up to 7x
faster" using a compression program that squeezes images, text/html,
and SWF flash animations prior to transmission across the phone
The pre-compression operates much more efficiently than the on-the-fly
V.44 modems. Typically website text is compacted to 5%
thus increasing effective throughput to approximately 1000 kbit/s, and
JPEG/GIF/PNG images are lossy-compressed to 15–20% (increasing
throughput up to 300 kbit/s).
The drawback of this approach is a loss in quality, where the graphics
acquire compression artifacts taking on a blurry or colorless
appearance; however the perceived speed is dramatically improved. (If
desired the user may choose to view uncompressed images instead, but
at a much slower load rate.) Since streaming music and video are
already compressed at the source, they are typically passed by the ISP
List of dial-up speeds
See also: List of device bandwidths
Note that the values given are maximum values, and actual values may
be slower under certain conditions (for example, noisy phone
110 baud (Bell 101)
(110 bits per second)
300 baud (
Bell 103 or V.21)
1200 baud (
Bell 212A or V.22)
2400 baud (V.22bis)
2400 baud (V.26bis)
4800 baud (V.27ter)
9600 baud (V.32)
14.4 kbit/s (V.32bis)
28.8 kbit/s (V.34)
33.6 kbit/s (V.34)
56k kbps (V.90)
56k kbps (V.92)
Hardware compression (V.92/V.44)
56.0 to 320.0 kbit/s
Server-side web compression
200.0 to 1000.0 kbit/s
^ Hauben, Michael; Hauben, Rhonda (1997). Netizens: On the History and
Impact of Usenet and the
Internet (1st ed.). Los Alamitos, CA: IEEE
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^ Kaspersky Technical Support website [search "dial up" slow] July 17,
^ Alexis C. Madrigal (June 1, 2012). "The Mechanics and Meaning of
That Ol' Dial-Up
Modem Sound". The Atlantic. Archived from the
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^ Pavel Mitronov. "
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^ "EarthLink Dial-Up
Internet service – fast, reliable dialup access
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