[D0106AAO], Letter from Thomas Alva Edison to William Edgar Gilmore, July 1901
https://edisondigital.rutgers.edu/document/D0106AAO
Transcription
I understand that several Railroads intend trying the experiment of substituting telephone for teleg to do away with the great expense of teleg operators. But to make this system a success it will be necessary to have everything recorded at both ends. Of course it could easily be recorded at both ends. Of course it could easily be recorded at the sending end as opr speaking into a tube leading to phono +telephone simultaneously could get the record if this will satisfy Foley, it is an easy matter to make a phonograph that one cylinder would run 1/2 a day but when it comes to recording from the distant and practically that is very difficult. If Foley will correspond with his fellow supts in the assn + gets assurances of cooperation as to use I would if the assurances would warrant it. Try and devise a satisfactory system to meet the demand I should want a little of the great annual saving or R.R. Co would make + will not attempt it without some tangible assurances of a fair treatment, you can show this to Foley Edison