This site is a non-commercial reference dedicated to the history and technology of modems — from the telegraph experiments of the 1830s to the 5G chipsets of the present day. It exists because the modem is one of the most consequential pieces of technology of the past two centuries, and its story is less well documented than it deserves.
The modem connected the world. Not metaphorically, not gradually, but literally and at a specific historical moment: when dial-up internet arrived in ordinary households in the 1990s, it changed what those households were. The modem was the device that made that change possible. Before it, a computer was a tool. With it, a computer was a window. That transition deserves a thorough account.
The site covers six broad epochs, each with its own dedicated history page:
» Epoch I — Telegraph, theory, and the first signals (1837–1950)
» Epoch II — Birth of the modem (1950–1980)
» Epoch III — The PC era and BBS culture (1980–1996)
» Epoch IV — Peak dial-up: 56k and the end of an era (1996–2000)
» Epoch V — The broadband revolution (2000–2010)
» Epoch VI — Mobile modems and the wireless world (2000–today)
The Technology section provides a detailed technical reference covering modulation schemes, channel physics, handshake protocols, error correction, DSL architecture, and mobile network design. The Catalog documents key modem hardware from each era. The Stories section covers the cultural dimension: what the dial-up era was actually like to live through.
The site is built in plain PHP and HTML, with no database and no JavaScript frameworks. It is intentionally simple. Content is more important than infrastructure.
The following sources were consulted in the preparation of this site's content. Where possible, primary sources and peer-reviewed technical publications have been preferred over secondary accounts.
» ITU-T Recommendation V.21 (1964, revised 1988) — 300 bps modem
» ITU-T Recommendation V.22 (1980) — 1200 bps modem
» ITU-T Recommendation V.32 (1984, revised 1993) — 9600 bps modem
» ITU-T Recommendation V.34 (1994, revised 1998) — up to 33,600 bps
» ITU-T Recommendation V.42 (1989, revised 2002) — error correction
» ITU-T Recommendation V.42bis (1990) — data compression
» ITU-T Recommendation V.90 (1998) — 56,000 bps downstream
» ITU-T Recommendation V.92 (2000) — enhancements to V.90
» ITU-T Recommendation G.992.1 (1999) — ADSL (G.dmt)
» ITU-T Recommendation G.992.5 (2003) — ADSL2+
» CableLabs DOCSIS 1.0 Specification (1997)
» CableLabs DOCSIS 3.0 Specification (2006)
» 3GPP TS 36.211 — LTE physical layer specification
» 3GPP TS 38.211 — 5G NR physical layer specification
» Nyquist, H. (1928). "Certain topics in telegraph transmission theory." Transactions of the AIEE, 47(2), 617–644. The paper that established the Nyquist sampling theorem and the concept of the symbol rate limit.
» Shannon, C.E. (1948). "A mathematical theory of communication." Bell System Technical Journal, 27(3), 379–423. The founding document of information theory, containing the Shannon–Hartley capacity formula.
» Ungerboeck, G. (1982). "Channel coding with multilevel/phase signals." IEEE Transactions on Information Theory, 28(1), 55–67. The paper introducing trellis-coded modulation, which enabled V.32 and V.34.
» Cioffi, J.M. et al. (1991). "ADSL: A new twisted-pair access to the information highway." IEEE Communications Magazine, 33(4), 34–45. The paper that established DMT as the modulation scheme for ADSL.
» Hafner, K. & Lyon, M. (1996). Where Wizards Stay Up Late: The Origins of the Internet. Simon & Schuster. A thorough account of ARPANET's creation, covering the modem infrastructure that underpinned it.
» Salus, P.H. (1994). A Quarter Century of UNIX. Addison-Wesley. Covers the early computing culture in which dial-up modems played a central role.
» Goldsmith, J. & Wu, T. (2006). Who Controls the Internet? Oxford University Press. Contextualises the ISP era and the dial-up internet's social impact.
» Forney, G.D. & Ungerboeck, G. (1998). "Modulation and coding for linear Gaussian channels." IEEE Transactions on Information Theory, 44(6), 2384–2415. Technical reference for the modulation theory underlying high-speed dial-up modems.
» Computer History Museum (computerhistory.org) — extensive archive of modem hardware, oral histories with engineers, and primary source documents from Bell Labs, Hayes, and US Robotics.
» Textfiles.com (textfiles.com) — Jason Scott's archive of BBS-era text files, FidoNet messages, and BBS lists. An invaluable primary source for BBS culture.
» Sixteen Colors (sixteencolors.net) — archive of ANSI and ASCII art from the BBS era, preserving the visual culture of the period.
» Wikimedia Commons (commons.wikimedia.org) — source for public domain and Creative Commons-licensed photographs of modem hardware referenced throughout this site.
» ITU-T (itu.int) — the International Telecommunication Union's official repository of V-series and G-series recommendations, many of which are freely available.
» RFC Editor (rfc-editor.org) — archive of IETF Request for Comments documents covering internet protocols that ran over dial-up modems (PPP, SLIP, and their successors).
Every effort has been made to ensure the technical and historical accuracy of the content on this site. Where sources conflict — as they sometimes do on questions of precise dates, first deployments, and performance specifications — the most conservative and best-documented claim has been preferred. Errors and corrections are welcome: if you find a factual mistake, please get in touch via the contact details below.
The original text content of this site — the History pages, Technology reference, Catalog descriptions, Stories, and this page — is published under the Creative Commons Attribution 4.0 International (CC BY 4.0) license.
This means you are free to:
» Share — copy and redistribute the material in any medium or format
» Adapt — remix, transform, and build upon the material for any purpose, including commercially
Under the following terms:
» Attribution — you must give appropriate credit to modem19.com, provide a link to the license, and indicate if changes were made
» No additional restrictions — you may not apply legal terms or technological measures that legally restrict others from doing anything the license permits
The full text of the CC BY 4.0 license is available at creativecommons.org/licenses/by/4.0.
Images referenced or used on this site are sourced from Wikimedia Commons and other repositories under their respective licenses (primarily public domain or CC BY / CC BY-SA). Each image recommendation in the catalog and history pages notes the suggested source. If you use images from this site, please verify the license of each image independently at its original source.
The CSS template used as the visual framework of this site was originally designed by TemplateMo (templatemo.com) and is used in accordance with their free template license.
This site would not exist without the work of the engineers, historians, and archivists who have documented the history of data communications over the past several decades. A few deserve particular mention.
Harry Nyquist and Claude Shannon established the mathematical framework within which every modem ever built has operated. Their papers, published in 1928 and 1948 respectively, remain models of scientific clarity and are freely available online. Anyone interested in the deeper theory of communication should read them in the original.
Jason Scott and the team at Textfiles.com have preserved an extraordinary quantity of BBS-era material that would otherwise have been lost. The Stories section of this site would have been poorer without access to the primary sources his archive maintains. His documentary BBS: The Documentary (2005) is the definitive filmed account of that culture and is freely available online.
The Computer History Museum in Mountain View, California maintains one of the finest collections of computing hardware and documentation in the world, including significant modem-related material. Their oral history programme has preserved the recollections of engineers who built the devices described on this site.
The ITU-T Study Group 16, which has maintained the V-series modem standards since 1964, and the engineers of Bell Labs, Hayes Microcomputer Products, US Robotics, Rockwell International, Qualcomm, and the dozens of other companies whose work is described here: the history of the modem is their history, and this site is an attempt to do it justice.
The BBS sysops who ran their boards through the 1980s and 1990s — on their own time, at their own expense, for the benefit of whoever cared to call in — built the first mass online communities. They deserve more recognition than they typically receive.
modem19.com — last updated April 2026. Content published under CC BY 4.0.