Dating an old western electric telephone
Since the first successful model of the telephone in 1876, each successive telephone operates on the same baic priciples that Bell introduced in his Boston workshop.
The designs and sizes of wall phones have changed from large wooden devices to the stylish Trimline ® phone introduced in 1965.
If, however, the transmitter is to be used for common battery working, only about one-half the amount of granules (8.8 grains) is used, in order to increase the resistance.
The diaphragm is 2 1/2 inches in diameter and .022 inches in thickness, and the carbon cell is 5/8 inch internal diameter.
485311 for his Solid Back Transmitter on 1st November 1892. This transmitter had minor deficiencies but was used well into the 1930s.The Blake was quite large and needed a box of its own, the batteries were the early glass cell types and were quite bulky, and the magneto generator was tall and heavy and shared the top box with the coil and ringer.A smaller transmitter designed by Berliner was available to the Bell company but it may have caused legal problems with Edison's carbon transmitter so it did not enter production.Packing is where the carbon granules settle to the bottom of the transmitter and reduce its efficiency.Deckert's modification to the Hunnings improved the packing problem slightly, but a new transmitter was obviously needed.