PUBLIC SWITCHED DIGITAL SERVICE


Public Switched Digital Service is a

Pacific Bell Service that offers the

user flexible high-speed data

transmission capabilities with costs

based on usage.  Public Switched

Digital Service allows the switchable

transmission of data between multiple

locations at the rate of 56 Kbps.  At

this rate a letter-sized document can

be transmitted in 4 seconds.
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Thanks to a new Bell Laboratories

technology known as Time Compression

Multiplexing, Public Switched Digital

Service allows the customer to use the

installed wiring, normally used to

place voice calls, to place high speed

data calls. 








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The Pacific Bell Central Office (CO)

acts as the hub for Public Switched

Digital Service and uses the normal 2-

wire telephone loop to the user's

premises, instead of the 4-wire loop

usually required to provide Digital

Data Service.  Public Switched Digital

Service is accessed just by making a

telephone call using a special access

code. 


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Examples of how this service could be

used are bulk data transfer, batch

transmissions, high speed dial backup,

and video teleconferencing.  Any user

who has intermittent peak data

transmission loads and/or has three

hours of uninterrupted usage a day will

find this service economical and

useful.





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For more information on Pacific Bell's

Public Switched Digital Service, call:

         1-(800) PAC-DATA










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