Bell 103 modem

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Bell 103 modem" – news · newspapers · books · scholar · JSTOR (August 2023) (Learn how and when to remove this message)

The Bell 103 modem or Bell 103 dataset was the second commercial

• 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.

Applications

Bell 103 modulation is still in use today, in shortwave radio, amateur radio, and some commercial applications. Its low signalling speed and use of audio frequencies makes it suitable for noisy or unreliable narrowband links.

For example, the

The American synth-pop band Information Society featured a track entitled "300bps N, 8, 1 (Terminal Mode or Ascii Download)" on their album Peace and Love, Inc. that could be decoded to a text message by holding a phone handset connected to a Bell 103 modem up to the speaker playing the track.

See also

• Bell 202 modem
• List of device bandwidths

External links

• PACE is a message terminal that transmits messages over voice circuits

References