This folder contains correspondence and other documents pertaining to the Edison Phonoplex System of Telegraphy. Much of the correspondence is by W.S. Logue, field agent for the phonoplex system, and is addressed to Edison's secretary, A.O. Tate, or to Tate's assistant, Thomas Maguire. Edison himself was only tangentially involved in phonoplex operations, and very few letters to or from him can be found in this folder. Among the documents for 1893 are letters discussing the attitude of Western Union toward the phonoplex and two summary income and expense statements for 1892 and 1893.

Approximately 10 percent of the documents have been selected. Most of the unselected documents involve routine installation and maintenance matters on various American and Canadian railroads, particularly the Illinois Central Railroad and the Central Railroad of Georgia. Also not selected are Logue's accounts and personal correspondence.

Related material can be found in D-93-20 (Edison Manufacturing Co. - General).