ResonantLive Sound Archive

Equipment file · Telephone transmitter

Blake transmitter

Francis Blake · 1878–1879

Evidence status · documented

Identity and core specifications are documented; some historical fields remain unavailable.

Francis Blake Jr., a former US Coast Survey physicist, developed a carbon transmitter patented in Britain in January 1879. Paired with Emile Berliner's contact principle, the Berliner–Blake transmitter became the Bell standard for most of the 1880s, mounted as the top box of three-box wall telephones.

Introduced
1878–1879
Category
Telephone transmitter
Intended use
Battery-powered carbon transmitter for standard telephone service
Production
Made by Western Electric and other Bell licensees through the 1880s

Equipment photographs · 2

PSM V70 D409 Blake telephone transmitter

1 / 2 · PSM V70 D409 Blake telephone transmitter

PSM V70 D409 Blake telephone transmitter·Popular Science Monthly, vol. 70 (1907)·Public domain

Why it mattered

  1. 01

    It gave Bell licensees a reliable carbon transmitter inside the Bell patent portfolio.

  2. 02

    It was the standard transmitter on the earliest mass-produced Western Electric telephones.

Engineering record

Diaphragm mounting
US 250,126 (1881) describes a diaphragm on a ring seat with flat springs pressing its centre, allowing thermal expansion while damping false vibrations[1]
Commercial pairing
Combined with Berliner's variable-contact principle as the Berliner–Blake transmitter[2]

Original pricing

No reliable period price located

2026 equivalent

Not calculated without a reliable original price.

Public price evidence was not sufficient to publish a defensible original figure.

Use in the field

Standard transmitter on Western Electric's three-box wall telephones from about 1882[3]

Manuals & original documents

Sources

  1. 1US250126 — Speaking TelephoneUS Patent Office · patent · 1881
  2. 2Blake Transmitter, Page 3: Berliner and Blaketelephonecollecting.org · reference
  3. 3Western Electric Telephonestelephonecollecting.org · reference

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