Downtown in Sacramento in Sacramento County, California — The American West (Pacific Coastal)

First Commercial Modem

Photographed by Sean P. Flynn, February 9, 2025

1. First Commercial Modem Marker

Inscription. AT&T introduces the first commercial modem in 1958.

Topics. This historical marker is listed in these topic lists: Communications • Industry & Commerce. A significant historical year for this entry is 1958.

Location. 38° 34.72′ N, 121° 29.209′ W. Marker is in Sacramento, California, in Sacramento County. It is in Downtown. It is on J Street west of 15th Street, on the left when traveling east. Touch for map. Marker is in this post office area: Sacramento CA 95814, United States of America. Touch for directions.

Regionally, this marker is in Sacramento Valley

and specifically in the Central Valley.

It is also on the American Pacific Coast.

Globally, it is in North America,

on the Ring of Fire,

in the Pacific Rim,

in the Western Hemisphere,

in the Western World,

and in the Anglosphere.

Historically, it finds itself in what was once New Spain

and also Mexico’s Alta California.

Other nearby markers. At least 8 other markers are within walking distance of this marker: Bell Solar Battery (here, next to this marker); Telstar I Satellite (here, next to this marker); Bell Labs Sea Plow (a few steps from this marker); Sacramento Memorial Auditorium (a few steps from this marker); 1958 Directory Operators (a few steps from this marker); The Messiah, 1928 (a few steps from this marker); The Invention of the Transistor (a few steps from this marker); Boxing at the Sacramento Memorial Auditorium (a few steps from this marker). Touch for a list and map of all markers in Sacramento.

More about this marker. The marker and photo is one of a set of 29 found around two A&T-owned buildings along 14th, J and 15th Streets.

Also see . . . From Baud to Awed: The History of the Modem.

Excerpt:
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"By 1959, a commercial version of the SAGE modem was released as the Bell 101 by AT&T. Called a “dataset” rather than a modem, the Bell 101 could send or receive data at 110 bits (0.11kb) per second. It was also only half-duplex–meaning it could either send or receive data, but not both at the same time. Not only was the Bell 101 the first commercial modem, but it was also the first commercial device to use ASCII to encode text."

(Submitted on February 13, 2025, by Sean P. Flynn of Oak Park, Illinois.)

First Commercial Modem photo and marker image. Click for full size.

Photographed by Sean P. Flynn, February 9, 2025

2. First Commercial Modem photo and marker

AT&T Building markers along J Street image. Click for full size.

Photographed by Sean P. Flynn, February 7, 2025

3. AT&T Building markers along J Street

This First Commercial Modem photo is just off camera, at the base of the second building on the far right of the photo.

Credits. This page was last revised on February 13, 2025. It was originally submitted on February 13, 2025, by Sean P. Flynn of Oak Park, Illinois. This page has been viewed 159 times since then and 47 times this year. Photos: 1, 2. submitted on February 13, 2025, by Sean P. Flynn of Oak Park, Illinois. 3. submitted on February 12, 2025, by Sean P. Flynn of Oak Park, Illinois.