It has been suggested that this article or section be merged into Modem. (Discuss)

56k modems are voiceband modems capable of speeds near 56 kbit/s when connecting to a service that has ISDN or other digital connection to the phone network. Wikipedia does not have an article with this exact name. ... A modem (from modulate and demodulate) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. ... In electronics, voiceband means the typical human hearing frequency range that is from 20Hz to 20KHz. ... A modem (a portmanteau word constructed from modulator and demodulator) is a device that modulates an analog carrier signal (sound), to encode digital information, and that also demodulates such a carrier signal to decode the transmitted information. ... 56 kbit/s (56 kilobits per second) is the data rate of a normal single channel digital telephone line in North America. ... ISDN is also short for isosorbide dinitrate Integrated Services Digital Network (ISDN) is a type of circuit switched telephone network system, designed to allow digital (as opposed to analog) transmission of voice and data over ordinary telephone copper wires, resulting in better quality and higher speeds, than available with analog...

It is important to note that this technique cannot be used between two 56k modems and that when two 56k modems connect, they will revert to slower standard analog methods.

At the end of 1997 there were two rival modem designs using this technique: k56flex and U.S. Robotics' X2 chipset. In February 1998 the ITU proposed a 56 kbit/s standard called V.90, which was formally approved during September 1998. A modem (from modulate and demodulate) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. ... K56flex (originally called the K56Plus) was a modem chipset from Rockwell and Lucent that gave users the possibility of receiving data on ordinary phone lines at 56 kbit/s as opposed to the previous maximum of 33. ... U.S. Robotics (popularly referred to by its acronym USR) is a company that makes computer modems and related technologies. ... US Roboticss 56K modem protocol for upload under V.34+ at 33. ... The International Telecommunication Union (ITU; French: Union internationale des télécommunications, Spanish: Unión Internacional de Telecomunicaciones) is an international organization established to standardize and regulate international radio and telecommunications. ... V.90 is an ITU-T recommendation for a modem, allowing 56 kbit/s download and 33. ...

The first commercial duplex modem was invented by AT&T in 1962, called the Bell 103. It had a speed of 300 bits/s, or 0.3 kbit/s. That speed increased to 14.4 kbit/s, then doubled to 28.8 kbit/s, and in 1996, Brent Townshend invented the 56 kbit/s modem.

Today, the 56k modem has become obsolete yet millions are made every year to serve the millions of people in the developing world or in remote parts of the rural developed world without highspeed Internet service, or who do not use the high speed connections they could get.

The reason a 56Kb modem cannot reach download speeds faster than 7kB/s is due to a conflict of abbreviations. The 'K' as in '56Kb modem' stand for 'Kilobits'. The 'kB' in '7kB/s' stands for 'Kilobytes' So in reality, 56Kb and 7kB are about the same speed. A kilobit is a unit of information, abbreviated kbit, sometimes also kb. ... Depending on the context in which it is used, the word kilobyte may mean either 1,000 or 1,024 bytes. ...

Kb = Kilobit
kB = Kilobyte A kilobit is a unit of information storage, abbreviated kbit or sometimes kb. ... A kilobyte (derived from the SI prefix kilo-, meaning 1000) is a unit of information or computer storage equal to the decimal 1024 bytes (2 to the 10th power, or 1,024 bytes based in the binary system). ...

8 bits = 1 byte
56,000bits = About 7,000 (7kB) bytes

However, due to level restrictions, phone line quality and other factors, obtaining this theoretical maximum throughput for a dial up modem is technically impossible.

External links

• Brent Townshend

References

This article was originally based on material from the Free On-line Dictionary of Computing, which is licensed under the GFDL. This article does not cite any references or sources. ... Bold text // “GFDL” redirects here. ...