Popular Mechanics, April, 1910, pages 489-490:

Home reception     Phonographic music, carried over the wires from the central telephone exchange to the homes of the subscribers to this unique service, is a novelty tried out with such success in Wilmington, Delaware, that the idea may spread to other cities. The music is carried by the regular telephone wires, but those who subscribe for it must have a special receiver beside the regular telephone box. This receiver, to which a phonograph horn is attached, throws a large volume of sound into the room.
    At the central telephone exchange is a music room, which contains a number of phonographs, and an operating board to which the wires of the music subscribers are attached. Each subscriber to the music service is supplied with a special directory giving names and numbers of records. When music is desired, the subscriber calls the music department on the telephone, asks for a certain record, and screws the horn into position. The music operator plugs up a free phonograph to the line, slips on a record, and starts the machine. At the conclusion of the piece the connection is pulled down, unless more records have been requested.
    When several subscribers call for the same piece all the wires can be connected to the one phonograph. The telephone company requires each musical subscriber to guarantee $18 per year. The rate of charge for the service is 3 cents for ordinary records, and 7 cents for grand opera.
Phonograph room