George M Phelps US Patent Electric Speaking Telephones 214,840 4-29-1879 Phelps Transmitter and Arm

[featured_image]
Download
  • Version
  • Download 16
  • File Size 94.64 KB
  • File Count 1
  • Create Date July 19, 2020
  • Last Updated July 19, 2020

George M Phelps US Patent Electric Speaking Telephones 214,840 4-29-1879 Phelps Transmitter and Arm

Attached Files

File
George M Phelps US Patent Electric Speaking Telephones 214,840 4-29-1879 Phelps Transmitter and Arm.pdf