1911 Automatic Electric Residence Set (Wall Phone) with Mercedes Dial.

This Automatic Electric phone is one of many versions of the residence set (Wall Phone) with the same type of button. Most all seem to be party line phones and most have frequency ringers. This one is different in that the schematic shows it was used with an extension phone. It is a series circuit and it is not used with a common booster subset. The button bypasses the voice circuit and makes a loop from L- to ground. It uses simplex (ground return) dialing. The dial always pulses a ground loop (simplex) but if the button isn’t pressed, the speech circuit is enabled between digits. The button is there as an “off hook” signal for the CO pulse relays. It will also stop the receiver from clicking between digits.

This 1911 Automatic Electric Residence Set (Wall Phone) was tested on a home phone line using a line cord Green positive to (+) and Red negative to (–) on the phone. It had dial tone. Sent call from cell phone, it didn’t ring. But it could be answered and talk back and forth. The transmitting and receiving were crystal clear! It could dial out, but the dial would not break dial tone. With dial tone sound to the receiver, pushing the button causes it break dial tone just like the button on a NE Contempra handset. It hangs up the phone. This phone could be used as an answering extension. The ringer was tested with a 9 volt battery causing the ringer clapper to move striking the gongs.

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