ISP Information:
Rate of transmission speed in a signal - the number of changes of state, such as voltage or frequency, per second in a signal. Named for the French teleprinter inventor Baudot. In simplest systems, it is synonymous with bits per second. In more complex systems, a baud may include more than one bit.
ISP Glossary:
baud - Through the 1930s, making a far long distance call on the Bell Systemwas serious business. It was very expensive, and required a numberof operators to set the call up. It was known as "delay" calling.Years later, the system had enough capacity and automation sothat a local operator could quickly place a call without delay.This was known as "demand" calling.I was wondering when the bulk of the Bell System was able to make"demand" calls. (Obviously the whole system didn't switch at once,even into the 1970s some obscure locations were manually reached byold style operator "build up".) Was it ok around 1940? (Obviouslythe war years don't count due to traffic volume; although how hard wasit to make a moderate call on a main route such as Boston to NYC orNYC to Washington? Could your dial 0 operator or basic long distanceoperator do it quickly)?Initially:They had little long distance line capacity since a wire could onlycarry a few conversations with the technology available. Repeatersand loading were expensive and tricky.Because of limited capacity, calls were made on a 'delay' basis. Thatmeant a customer requested a call, and was then called back when thecall was finally set up. First a line had to be available. Then theconnection built up from city to city until the ultimate desired party(directory assistance had to supply the number since most peoplecalled by name back then.) Routing had to take into account linecharacteristics so that echo and problems were kept down-- too manyintermediate junction points would degrade transmission.But in the 1930s electronics improved greatly and better transmissionand carrier systems were developed. As more experience was gained,the call set up process was streamlined.Around 1940, the Bell System was planning significant automation butWW II intervened. (They did install a #4 crossbar in Phila during thewar which helped).After WW II, the Bell System installed #4 crossbar, created uniformnumbering for the nation, installed microwave and coaxial cable forhigh capacity channels; all of which allowed faster calling.
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