Editing Softmodem (section)

== History ==
The first generations of hardware modems (including [[acoustic coupler]]s) and their protocols used relatively simple modulation techniques such as [[Frequency Shift Keying|FSK]] or [[Amplitude Shift Keying|ASK]] at low speeds. Under these conditions, modems could be built with the analog [[discrete component]] technology used during the late 70s and early 80s.

As more sophisticated transmission schemes were devised, the circuits grew in complexity substantially. New modulation required mixing analog and digital components, and eventually incorporating multiple [[integrated circuit]]s (ICs) such as logical gates, [[Phase-locked loop|PLL]]s and [[microcontroller]]s. Later techniques used in modern [[ITU-T V.34|V.34]], [[ITU-T V.90|V.90]] and [[ITU-T V.92|V.92]] protocols (such as a 1664-point [[Quadrature amplitude modulation|QAM]] constellation) are so complex that implementing them with discrete components or general purpose ICs became impractical.

Furthermore, improved compression and error correction schemes were introduced in the newest protocols, requiring extra processing power in the modem itself. This made the construction of a mainly analog/discrete component modem impossible. Finally, compatibility with older protocols using completely different modulation schemes would have required a modem made with discrete electronics to contain multiple complete implementations.

Initially the solution was to use [[Large-Scale Integration|LSI]] [[Application-specific integrated circuit|ASICs]] which shrank the various implementations into a small number of components, but since standards continued to change, there was a desire to create modems that could be upgraded.

In 1993, Digicom marketed the ''Connection 96 Plus'', a modem based around a [[Digital signal processor|DSP]] which was programmed by an application on startup. Because the program was replaceable, the modem could be upgraded as standards improved. Digicom branded this technology ''SoftModem'', perhaps originating the term.<ref name=":0" />

Likewise, the term "Winmodem" originated by Prof. Parvaiz Akhtar in 1996 with hardware being developed by [[USRobotics|USRobotics']] ''Sportster Winmodem'', a similarly upgradable DSP-based design.<ref>{{Cite magazine |title=U.S. Robotics modem users to get soft upgrade to 33.6Kbps |last=Lee |first=Yvonne L. |work=InfoWorld |publisher=InfoWorld Media Group, Inc. |date=1996-06-10 |page=58 |volume=18 |issue=24 |url=https://archive.org/details/bub_gb_tD0EAAAAMBAJ|access-date=2020-08-14 |via=Internet Archive }}</ref>

In 1996, two types of modem began to reach the market: ''host-based'' modems, which offloaded some work onto the host CPU, and ''software-only'' modems which transferred all work onto the host system's CPU.<ref name=":1" /> In 1997, the [[AC'97]] standard for computer audio would introduce channels for modem use, making software modem technology common in PCs.

Since then, some softmodems have been created as standalone software projects utilizing standard sound card interfaces, such as an experimental open-source 96&nbsp;kbit/s leased-line softmodem called AuDSL from 1999,<ref>{{cite web |title=AuDSL - a software leased line modem |url=https://www.araneus.fi/audsl/ |website=www.araneus.fi |quote=AuDSL is an experimental software modem for low-speed Internet connectivity over leased copper lines using PC sound cards as the line interface. The acronym AuDSL stands for Audio Digital Subscriber Line.}}</ref> and the Minimodem project which implements several FSK modem standards.<ref>{{cite web |title=minimodem - general-purpose software audio FSK modem |url=http://www.whence.com/minimodem/ |website=www.whence.com |quote=It acts a general-purpose software FSK modem, and includes support for various standard FSK protocols such as Bell103, Bell202, RTTY, TTY/TDD, NOAA SAME, and Caller-ID.}}</ref>