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Devices and hardware

Dial-up modem

Summary

A dial-up modem connects a computer to the internet over an ordinary telephone call, turning data into signals the phone network can carry and back again. Speeds were set by ITU-T standards, from V.32 bis at 14,400 bit/s (1991) to V.90 at 56,000 bit/s (1998) and V.92 (2000). Services such as AOL signed up millions of members this way before broadband replaced it in the 2000s. AOL ended its dial-up service on September 30, 2025, the date given in an AOL notice as reported by Tom's Hardware.

Web Building Encyclopedia · Devices and hardware · Last reviewed October 22, 2026 · 10 min read

What a dial-up modem was

A dial-up modem let a computer reach the internet by placing an ordinary telephone call. The device turns digital data into signals that can travel over a phone line, and turns the signals it receives back into data.

The call usually went to an internet service provider, a company with banks of modems waiting to answer. Once the two modems were connected, the computer could load pages from the World Wide Web, send email and use other services. When the call ended, so did the connection.

The Federal Communications Commission (FCC) describes broadband as high-speed internet access that is much faster than “traditional dial-up” connections. Its consumer guide says even satellite broadband downloads much faster than dial-up.1

Speeds were measured in bits per second (bit/s), the number of ones and zeros sent each second. V.90, one of the last dial-up standards, allows up to 56,000 bit/s from the provider to the user and up to 33,600 bit/s in the other direction.2 For comparison, V.21, whose edition in force dates from 1988, covers a modem running at 300 bit/s.3

How a dial-up connection worked

A telephone line was built to carry the human voice, not data. A modem works within that limit by sending tones whose frequency, strength and timing change in patterns the modem at the other end can decode. Each standard defines those patterns, so that modems from different makers can talk to each other.

The patterns are published by ITU-T, the standards arm of the International Telecommunication Union, which describes itself as the United Nations agency for digital technologies.4 Its V-series Recommendations cover data sent over the telephone network.2 Before any data flows, the modems agree on a common method and speed. ITU-T Recommendation V.8, whose earliest listed version is dated September 1994, sets procedures for starting such sessions over the public telephone network.5

Modems also did two jobs beyond moving tones:

  • Error correction. Noise on a phone line can flip bits, so modems check data and resend damaged pieces.
  • Compression. Modems can shrink data before sending it. V.42 bis, dated January 1990, defines compression for modems that use error correction.6 V.44, approved in November 2000, is a later compression standard.7

The trick behind 56,000 bit/s

Inside the telephone network, calls could be carried as numbers rather than as sound. ITU-T Recommendation G.711 sets the usual method, pulse code modulation (PCM): the sound is measured 8,000 times a second, and each measurement is stored as eight binary digits.8 That works out to 64,000 bit/s for one call.

V.90 takes advantage of this. It defines a pair of modems: a digital modem at the provider, connected to a digital switched network through an interface such as a Basic Rate Interface (BRI) or Primary Rate Interface (PRI), and an analog modem at the user’s end. The way the digital modem connects to the network is left to each country.9 The digital modem generates G.711 signals and sends them downstream with PCM at 8,000 symbols a second. The user’s modem decodes them at rates from 28,000 to 56,000 bit/s, in steps of 8,000/6 bit/s. In the upstream direction, from the user to the provider, V.90 uses the older V.34 method.9

This is why 56,000 bit/s only worked in one direction, and only when the provider had a digital connection to the phone network. Earlier standards such as V.34 were written for two modems on ordinary telephone circuits.10

From V.32 bis to V.90 and V.92

Each new standard raised the top speed. The dates below are the versions listed by ITU-T; some older Recommendations show only the 1988 edition still in force.

RecommendationVersion dateTop speedWhat it added
V.22 bisNovember 19882,400 bit/sDuplex modem using the frequency division technique11
V.32November 1988 (revised March 1993)9,600 bit/sDuplex modems for the switched telephone network and leased lines12
V.32 bisFebruary 199114,400 bit/sHigher speed on the same kinds of circuits13
V.34September 1994 (revised October 1996 and February 1998)28,800 bit/s, then 33,600 bit/sFaster two-way speeds; the 1996 edition raised the limit to 33,600 bit/s10
V.90September 1, 199856,000 bit/s down, 33,600 bit/s upA digital and analog modem pair using PCM downstream2
V.92November 17, 200056,000 bit/s down, 48,000 bit/s upFaster upstream, quicker start-up, modem on hold1415

The 56K standards contest

Modems faster than 33,600 bit/s were on sale before there was an international standard, built on two competing systems called x2 and K56flex.16 In its annual report for the year ended June 30, 1997, America Online (AOL) called them “the two competing standards for high speed access” and said it was upgrading its network to support both.17

The ITU settled the contest early in 1998. TidBITS reported on February 16, 1998, that the ITU had set a 56K standard called V.90 that drew on both K56flex and x2, and that most large modem makers planned upgrades for existing 56K modems.16 ITU-T approved V.90 on September 1, 1998.2 By its fiscal 2000 report, AOL said it had upgraded its network to support V.90.18

V.92

V.92, approved on November 17, 2000, is titled “Enhancements to Recommendation V.90”.14 Its summary lists upstream speeds up to 48,000 bit/s, faster start-up on connections the modems have already recognized, and procedures to put a modem on hold when a call-waiting signal or an outgoing call request arrives.15 The modem-on-hold feature reflects a basic fact of dial-up: the internet session used the household’s telephone line.

AOL and the dial-up years

America Online was incorporated in Delaware on May 24, 1985.19 By 1996 it ran its own data network, AOLnet, which members reached with a local phone call.19

AOL’s filings show how quickly the service grew:

  • June 30, 1996. About 6.2 million members worldwide. AOLnet grew from 20,000 to 140,000 modems during the year and offered about 720 local numbers in North America at up to 28.8 kbps (28,800 bit/s).19 The standard plan cost $9.95 a month for up to 5 hours, and a 20-hour plan cost $19.95, with extra hours at $2.95.19
  • December 1, 1996. AOL switched to a flat monthly fee of $19.95 with no hourly charges. Average monthly use per member rose from about 7 hours in the first quarter of fiscal 1997 to about 18 hours in the fourth, and AOL reported network access problems for subscribers after the change.17
  • June 30, 1997. About 8.6 million members. AOLnet grew from 143,000 to 350,000 modems in the year, with about 880 local numbers in about 571 cities.17
  • June 30, 2000. About 23.2 million AOL members, plus about 2.8 million on CompuServe, which AOL also owned. The network had about 2.6 million modems worldwide, after additions of about 50,000 a month.18

The same 2000 report shows AOL preparing for faster connections. It described alliances with Verizon and SBC Communications for DSL, investment in cable modems and other technologies, and AOL Plus, launched in April 2000 for members on high-speed links.18 By then AOL also owned Netscape, maker of the Netscape Navigator browser, and on January 10, 2000, it had agreed to merge with Time Warner.18 Both deals are part of the story of the browser wars and the dot-com bubble.

The subscriber base then shrank. AOL Inc. reported about 2.2 million domestic subscribers at the end of 2014, down from 2.5 million in 2013 and 2.8 million in 2012, and said the number was expected to keep falling. Its paid plans still listed unlimited dial-up access among their features.20

The end of AOL dial-up

By August 2025, AOL had posted a notice on its help site titled “Dial-up Internet to be discontinued.”2122 As reported by Tom’s Hardware on August 9, 2025, the notice said “AOL routinely evaluates its products and services and has decided to discontinue Dial-up Internet.” According to that report, the notice set September 30, 2025, as the end date for the service, the AOL Dialer software and the AOL Shield browser.22 On October 1, 2025, Cox Media Group’s national content desk reported that AOL had turned off its dial-up service as of September 30.23

The shift to broadband

Broadband means a connection much faster than dial-up.1 In August 2000 the FCC used two speed levels: “high-speed” services of over 200 kbps in at least one direction, and “advanced” services of 200 kbps in both directions. It counted about 2.8 million high-speed subscribers in the United States at the end of 1999 and gave a penetration rate of 1.6% for high-speed and advanced services.24

Two technologies did most of the early work:

  • Cable modems. They carry data over cable television networks. ITU-T Recommendation J.112, dated March 1998, covers transmission systems for interactive cable television services.25
  • DSL. Digital subscriber line carries data over the existing telephone wire. The ITU-T standard for asymmetric DSL (ADSL), G.992.1, is dated July 1999.26 The FCC notes that ADSL works over the same line as voice service without disrupting regular phone calls.1

What the surveys show

US government and Pew Research Center surveys trace the switch:

  • 1997. The Current Population Survey found that 18% of households used the internet, in the first year it asked.27
  • 2000. Pew’s trend data shows that 52% of adults used the internet in 2000 and 1% had home broadband in March 2000.28 A 2013 Pew article gives a figure for households rather than adults: 3% of American households had broadband in June 2000.29
  • 2001 to 2003. A Commerce Department report, using Census Bureau survey data, found that household broadband rose from 9.1% in September 2001 to 19.9% in October 2003, while dial-up households fell from 40.7% to 34.3%.30
  • December 2012. Pew found that 65% of Americans had home broadband and 3% still used dial-up at home. When Pew asked dial-up users in spring 2009 what would make them switch, 35% said a lower price, 17% said broadband becoming available where they lived, and 20% said nothing would.29
  • 2013. The American Community Survey found that 73.4% of households had a high-speed connection and only 1.0% connected by dial-up alone.31
  • 2021. The Census Bureau found that 90% of US households had a broadband subscription.32

The bar for “broadband” kept rising. On March 14, 2024, the FCC raised its fixed broadband benchmark to 100 Mbps download and 20 Mbps upload, replacing the 25/3 Mbps level set in 2015.33 100 Mbps is about 1,800 times V.90’s 56,000 bit/s. In its fact sheet updated October 19, 2026, Pew reports that 78% of US adults subscribe to home broadband, based on a survey conducted January 30 to June 18, 2026.28

Why page weight mattered

Page weight is the total size of everything a web browser downloads to show a page: the HTML, images, scripts, style sheets and fonts. On dial-up it set how long a visitor waited.

The arithmetic is simple. At the full 56,000 bit/s, a modem moves at most 7,000 bytes a second, before any overhead. A 100 KB page therefore takes about 15 seconds, and about 28 seconds at 28,800 bit/s. And 56,000 bit/s was a ceiling, not a promise: V.90 defines a range of downstream rates from 28,000 to 56,000 bit/s.9

Those waits ran past the limits usability research had set. In 1993 Jakob Nielsen described 10 seconds as the limit for keeping a user’s attention on the exchange with the computer, and 1 second as the limit for keeping their flow of thought unbroken.34

Web standards of the time made room for slow downloads. The W3C‘s HTML 3.2 Recommendation of January 14, 1997, says an image’s width and height let browsers reserve screen space for it before the image data arrives over the network.35 The HTTP Archive’s 2025 Web Almanac recalls that developers hand-optimized images and scripts “to ensure pages could crawl through 56k modems.”36

Page weight today

Pages have grown far beyond what dial-up could carry. The Web Almanac 2025 reports a median home page of 2,862 KB on desktop and 2,559 KB on mobile in July 2025. The mobile median was 845 KB in July 2015 and 505 KB in October 2014. The median mobile home page used 911 KB of images and 632 KB of JavaScript; images were the largest resource type by bytes, followed by JavaScript.36 The chapter also gives 2,362 KB at one point for the July 2025 mobile median; its charts and its 202.8% growth figure match 2,559 KB.36

By the same arithmetic, a 2,559 KB page would take more than six minutes over a perfect 56,000 bit/s connection. Slow links have not disappeared either. The ITU estimated in November 2025 that about 6 billion people were online and 2.2 billion were not, and it named speed as one of the factors behind the digital divide.4

Timeline

  1. AOL's dial-up internet service ends, along with the AOL Dialer software and AOL Shield browser, per AOL's notice as reported by Tom's Hardware22
  2. FCC raises its fixed broadband benchmark from 25/3 Mbps to 100/20 Mbps33
  3. Census Bureau report: 1.0% of US households used dial-up alone in 201331
  4. Pew Research Center reports that 3% of Americans use dial-up at home29
  5. Census survey data in a Commerce Department report: 19.9% of US households have broadband and 34.3% dial-up30
  6. ITU-T approves V.92, with upstream speeds up to 48,000 bit/s14
  7. FCC counts about 2.8 million US high-speed subscribers at the end of 199924
  8. AOL reports about 23.2 million members and about 2.6 million modems in its network18
  9. ITU-T publishes G.992.1, the ADSL standard26
  10. ITU-T approves V.90, the 56,000 bit/s standard2
  11. TidBITS reports that the ITU has agreed on a 56K standard combining x2 and K56flex16
  12. AOL starts a flat-rate plan of $19.95 a month with no hourly charges17
  13. V.34 is published for speeds up to 28,800 bit/s10
  14. V.32 bis is published for speeds up to 14,400 bit/s13
  15. America Online is incorporated in Delaware19

What it means for your website

Few visitors arrive by dial-up now, but the lesson of the modem years still applies: every kilobyte is time someone spends waiting, on a weak mobile signal, a crowded rural line or an older phone.

  • Know your page weight. As of July 2025 the median mobile home page weighed 2,559 KB, and images were the largest resource type, at a median of 911 KB.36 Open your own home page in Chrome DevTools, check the Network panel’s total, and compare it with that median.
  • Test on a slow connection. The Network panel’s throttling menu can emulate fast 4G, slow 4G or 3G, and you can add a custom profile for slower links.37 Load your key pages that way before a launch or redesign.
  • Shrink and size your images. Export photos at the size they are shown. The srcset attribute lets the browser choose a smaller file for a smaller screen, and loading=”lazy” defers images until they come near the viewport.38
  • Give images a width and height. Browsers have used these since HTML 3.2 to reserve space before the image arrives.35 Today the same step reduces layout shift as images load,38 which our glossary explains under Core Web Vitals.
  • Be careful with add-ons. JavaScript was the second-largest resource type, at a median of 632 KB on mobile home pages.36 Each chat widget, slider or tracking script adds to it, so remove the ones you no longer use.
  • Serve files from close by. A content delivery network keeps copies of your files near visitors, which shortens each request.

Our guide to how a website works explains what happens between a visitor’s click and a finished page.

See also

References

  1. What Is Broadband?. Federal Communications Commission, consumer guide. accessed October 22, 2026.
  2. V.90: A digital modem and analogue modem pair for use on the Public Switched Telephone Network (PSTN) at data signalling rates of up to 56 000 bit/s downstream and up to 33 600 bit/s upstream. ITU-T Recommendation, International Telecommunication Union. 1998-09-01. accessed October 22, 2026.
  3. V.21: 300 bits per second duplex modem standardized for use in the general switched telephone network. ITU-T Recommendation, International Telecommunication Union. accessed October 22, 2026.
  4. Global number of Internet users increases, but disparities deepen key digital divides. International Telecommunication Union, press release. 2025-11-17. accessed October 22, 2026.
  5. V.8: Procedures for starting sessions of data transmission over the public switched telephone network. ITU-T Recommendation, International Telecommunication Union. accessed October 22, 2026.
  6. V.42 bis: Data compression procedures for data circuit-terminating equipment (DCE) using error correction procedures. ITU-T Recommendation, International Telecommunication Union. accessed October 22, 2026.
  7. V.44: Data compression procedures. ITU-T Recommendation, International Telecommunication Union. accessed October 22, 2026.
  8. G.711: Pulse code modulation (PCM) of voice frequencies (text of the 11/88 Recommendation). ITU-T, International Telecommunication Union. 1988-11. accessed October 22, 2026.
  9. Recommendation V.90 (09/98), full text. ITU-T, International Telecommunication Union. 1998-09. accessed October 22, 2026.
  10. V.34: A modem operating at data signalling rates of up to 33 600 bit/s for use on the general switched telephone network. ITU-T Recommendation, International Telecommunication Union. accessed October 22, 2026.
  11. V.22 bis: 2400 bits per second duplex modem using the frequency division technique. ITU-T Recommendation, International Telecommunication Union. accessed October 22, 2026.
  12. V.32: A family of 2-wire, duplex modems operating at data signalling rates of up to 9600 bit/s. ITU-T Recommendation, International Telecommunication Union. accessed October 22, 2026.
  13. V.32 bis: A duplex modem operating at data signalling rates of up to 14 400 bit/s. ITU-T Recommendation, International Telecommunication Union. accessed October 22, 2026.
  14. V.92: Enhancements to Recommendation V.90. ITU-T Recommendation, International Telecommunication Union. 2000-11-17. accessed October 22, 2026.
  15. V.92 (11/00): Summary. ITU-T, International Telecommunication Union. 2000-11. accessed October 22, 2026.
  16. ITU Delivers 56K Modem Accord. Jeff Carlson, TidBITS. 1998-02-16. accessed October 22, 2026.
  17. America Online, Inc., Form 10-K for the fiscal year ended June 30, 1997. America Online, Inc., US Securities and Exchange Commission (EDGAR). 1997-09-29. accessed October 22, 2026.
  18. America Online, Inc., Form 10-K for the fiscal year ended June 30, 2000. America Online, Inc., US Securities and Exchange Commission (EDGAR). 2000-09-22. accessed October 22, 2026.
  19. America Online, Inc., Form 10-K for the fiscal year ended June 30, 1996. America Online, Inc., US Securities and Exchange Commission (EDGAR). 1996-09-30. accessed October 22, 2026.
  20. AOL Inc., Form 10-K for the fiscal year ended December 31, 2014. AOL Inc., US Securities and Exchange Commission (EDGAR). 2015-02-27. accessed October 22, 2026.
  21. Dial-up Internet to be discontinued. AOL Help. accessed October 22, 2026.
  22. AOL will end dial-up internet service in September, 34 years after its debut. Mark Tyson, Tom's Hardware, via Yahoo Tech. 2025-08-09. accessed October 22, 2026.
  23. Hanging up on dial-up: AOL pulls plug on dial-up service. Cox Media Group National Content Desk, WFTV. 2025-10-01. accessed October 22, 2026.
  24. Nationwide Survey of Subscription to High-Speed and Advanced Telecommunications Services Shows 2.8 Million Total Subscribers. Federal Communications Commission, news release. 2000-08-03. accessed October 22, 2026.
  25. J.112: Transmission systems for interactive cable television services. ITU-T Recommendation, International Telecommunication Union. accessed October 22, 2026.
  26. G.992.1: Asymmetric digital subscriber line (ADSL) transceivers. ITU-T Recommendation, International Telecommunication Union. accessed October 22, 2026.
  27. Computer and Internet Use in the United States: 2016 (ACS-39). Camille Ryan, US Census Bureau. 2018-08. accessed October 22, 2026.
  28. Internet, Broadband Fact Sheet. Pew Research Center. 2026-10-19. accessed October 22, 2026.
  29. 3% of Americans use dial-up at home. Joanna Brenner, Pew Research Center. 2013-08-21. accessed October 22, 2026.
  30. A Nation Online: Entering the Broadband Age. National Telecommunications and Information Administration and Economics and Statistics Administration, US Department of Commerce. 2004-09. accessed October 22, 2026.
  31. Computer and Internet Use in the United States: 2013 (ACS-28). Thom File and Camille Ryan, US Census Bureau. 2014-11. accessed October 22, 2026.
  32. Computer and Internet Use in the United States: 2021 (ACS-56). Daniela Mejía, US Census Bureau. 2024-06. accessed October 22, 2026.
  33. FCC Increases Broadband Speed Benchmark. Federal Communications Commission, news release. 2024-03-14. accessed October 22, 2026.
  34. Response Times: The 3 Important Limits. Jakob Nielsen, Nielsen Norman Group. 1993-01-01. accessed October 22, 2026.
  35. HTML 3.2 Reference Specification. World Wide Web Consortium (W3C Recommendation). 1997-01-14. accessed October 22, 2026.
  36. Page Weight, Web Almanac 2025. Richard Barret and Jamie Indigo, HTTP Archive. 2026-01-15. accessed October 22, 2026.
  37. Network features reference. Chrome DevTools documentation, Google. accessed October 22, 2026.
  38. <img>: The Image Embed element. MDN Web Docs, Mozilla. accessed October 22, 2026.

Web Building Encyclopedia. First published October 22, 2026. Last reviewed October 22, 2026. Every fact on this page is linked to a source we opened. Spotted an error? Write to [email protected].