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Alberta's Telephone Heritage
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Telephone Exchange/Wire Centre

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As telephone systems grew, switchboards grew larger. However, one operator could not reach enough connections to do all the work at one position and boards were linked in a series with an operator at each board.

The first automatic switching systems worked best with small networks. Edmonton had the first automatic system in Alberta, installed in 1908. Larger centres like New York and Toronto continued with manual systems until 1922. (The last of the manual equipment in New York was replaced by dial units in 1960.) Bill Lord, PABX repairman working on Wardair’s new SL-1-ACD

Early automatic systems were known as Step by Step because they made the connection in a series of steps as the number was dialed. The rotary dial sent electrical pulses which activated electromagnets in the switching unit. The electromagnets moved components into position to create the desired connection to the number you were calling.

Switching Technology
This brief video contains examples of telephone automatic switching technology. There are 3 main types of switching technology: Step by Step, X Bar, and Digital Electronic. The Step by Step switching technology is featured here. Watch!

The system components could get stuck so regular maintenance by switchmen was important. Apprentice switchmen learned on the job over a period of five or six years before they became journeymen. On Sundays, they were often on their own in the exchange building or wire centre. This offered a good learning experience if things were quiet but it was a real challenge if a storm created short circuits and the system began to overload.

When the Edmonton system was converted from three-wire to two-wire, service improved and complaints dropped from an average of fifteen complaints per telephone per year to two complaints per telephone per year.

The Step by Step equipment was bulky and needed large exchange buildings or wire centres. The equipment was also very noisy. As demand for telephone service continued to grow, more efficient and compact switching equipment was developed. The next advance was Crossbar. It was still an electro-mechanical system using electromagnets. However, it did not complete the circuit until all the digits in the phone number were dialed. This feature gave it more flexibility in routing calls. It could place more calls with fewer components. The first units in Alberta were installed in Calgary in 1958.


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