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The Bell DataPhone 300 used the same protocol as the Bell 103. This modem is from 1978.
The Bell 103 modem or Bell 103 dataset was the second commercial modem for computers, released by AT&T Corporation in 1963.[1][2] It allowed digital data to be transmitted over regular unconditioned telephone lines at a speed of 300 bits per second. It followed the introduction of the 110 baud Bell 101 dataset in 1958.
The Bell 103 modem used audio frequency-shift keying to encode data. Different pairs of audio frequencies were used by each station:
The originating station used a mark tone of 1,270 Hz and a space tone of 1,070 Hz.
The answering station used a mark tone of 2,225 Hz and a space tone of 2,025 Hz.
Although original Bell 103 modems are no longer in common use, this encoding scheme is referred to generically as "Bell 103 modulation", and any device employing it as "Bell 103-compatible" or "a Bell 103 modem".
For many years, higher-speed modems retained the ability to emulate the Bell 103, allowing a fallback method for data to be communicated at low speed if channel conditions deteriorated.
^Peter Ha (25 October 2010). "All-TIME 100 Gadgets: Bell 103". Retrieved 28 August 2023.
^Joseph J. Antinori (July 1989). "From Morse to Modems: A Brief History of Telecommunications". PC Magazine. p. 209.
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The modem for the 4-row ASCII service was the Bell 101 dataset, developed by 1958 for military applications. It is the direct ancestor of the Bell103 modem...
States in 1978. In the early 1990s, approaches to increase modem speeds to 56K were explored at Bell Labs, and early patents were filed in 1992 by Ender Ayanoglu...
original on 12 January 2018. Retrieved 11 January 2018. "USNO Master Clock modem time". Archived from the original on 2017-12-27. Retrieved 2018-01-15. Recommendation...
manufacturer of modems. The company is known for the Smartmodem, which introduced a control language for operating the functions of the modem via the serial...
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Hayes command set. North American Bell103-style modems (300 bit/s) were incompatible with UK in-band signalling (the modem tones would disconnect the call)...
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codes are common especially in wireless communication systems, broadband modem standards and modern copper-based high-speed LANs. The physical layer net...
copper pair. TWX later added a second ASCII-based service using Bell103 type modems served over lines whose physical interface was identical to regular...
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requires measures that also use up throughput. Wireless devices, BPL, and modems may produce a higher line rate or gross bit rate, due to error-correcting...
Says 103.4M Watched The Super Bowl". Associated Press – via TVNewsCheck. Patten, Dominic (February 5, 2018). "Eagles' 1st Super Bowl Win Draws 103.4M Viewers...
portal Companies portal Accounting scandals 1-Meg Modem Bay Networks Bell labs Bell Telephone Memorial Bell-Northern Research Busy override Canadian Industrial...
free, non-hierarchical channels of communication--whether by computer and modem, pen and ink, telephone, or face-to-face--are the front line of reclaiming...
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