Tuesday, 13 August 2013

Early Telephones

In the magneto phone, two large batteries were used to power the transmitter. A telephone company employee had to visit every telephone to replace the batteries about every six months. The first batteries were wet cells, containing corrosive acid, which would occasionally leak. Later on, dry cells were used.

In 1884 there were about 370 telephone subscribers served by the Atlanta Telephone Exchange and a telephone exchange also existed in Decatur. A call from Atlanta to Decatur was long distance. The charge was 15 cents for 5 minutes.

By this time, the switchboard had probably been expanded considerably. Although the details about Atlanta at this point are unknown, in other cities with a similar evolution, larger switchboards were built. These larger switchboards required a coordinated effort between multiple operators to complete each call. In the New Haven, Connecticut office, for example, there was a system of metal bars running horizontally across the room. One operator would connect the caller to one of these horizontal bars and then shout orders down to another operator, who connected the called subscriber to the same bar. The shouting apparently made it hard to hear customers and resulted in customers having to shout as well.

Around 1887, to solve some of these problems, the "multiple switchboard" was invented. This arrangement repeated each subscriber's line jack multiple times so that it appeared in front of each operator, allowing a single operator to connect a call to any subscriber in the office. Early versions of this system had problems too. For example, it was difficult to tell when a particular line was in use before connecting a call to it.

Source : www.atlantatelephonehistory.info/part1.html

Telephone In 18th Century

Telephones connected to The Atlanta Telephonic Exchange were of the "magneto" type. The first one of these was the Butterstamp phone.

The Butterstamp Phone - c1879Like the Box Phone, this phone had a combination receiver/transmitter. The phone is named after the hand-held piece that looked like a butter stamp that was common at the time. You had to talk into it and then quickly place it to your ear to listen. The white button was used to signal the operator.

The Butterstamp phone transmitted sound very poorly. It was soon replaced by the first magneto crank phones with the newly invented Blake Transmitter.

Three Box Magneto Phone - c1882The "Three Box Phone" consisted of three wooden boxes on the wall with a hand-held receiver, a Blake Transmitter, a magneto crank, and a battery box. To place a call, you turned the crank to ring the operator, then picked up the receiver. The operator would then answer. You gave the operator the name of the party that you wanted and the operator connected you.

At the end of your call you had to signal the operator to disconnect the call. To do this, you had to hang up the receiver and turn the crank to produce a short ring. This was called "Ringing Off".

Source : www.atlantatelephonehistory.info/part1.html