Data Communication Chap3
Terms
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- What are the three parts of a message block
-
1. header
2. text
3. trailer (or ending) - The wire pair that is used to connect individual telephone to a telephone exchange is called
- subscriber loop
- Which channel series is best suited for low-speed, multipoint communications between terminals
- 1000
- describe 3000 series circuit
-
mostly used for data transmisssion but can be used for voice.
* transmits between 7200-9600bps. - The transmission method that requires each transmitted character to be framed by a start and stop bit is
- Asynchronous
- What a the 3 communication channels used to transfer information
-
- simplex
- half-duplex
- full duplex - descibe series 4000
-
voice-grade described as a supervoice facility.
series 4002 is used primarily to send telephotographs. - What is the primary differecne between a series 2000 and 3000 circuit
- the method of testing 3000 circuits assures better line quality than that of 2000 circuit
- What controlls the routing of messages in a message-switching system
- The message switching center
- describe series 5000
- Broadband. for customers who require bulk communications between locations.
- How is the header in a message identified
- by the SOH(start of header) character and the STX (start of text character)
- What transmission method requires each transmitted character to be framed by a start and stop bit
- asynchronous
- What transmission facility is often used in place of microwave relay stations?
- Satellite relay
- A receiving terminal knows that it has received all the text of a message when
- ETX character is received
- What are the function of a computer at a message-switching center
-
1. samples telegraph lines periodically for messages
2. stores messages until they can be relayed
3. processes information contained in the header of a message - HOW IS DATA MOVED IN A LINE-SWITCHING NETWORK
- IT IS CONTROLLED BY THE TRANSMIT AND RECEIVED MODEM
- Describe series 1000 circuit
- 1000- subvoice, used for transmitting DC binary signals,low speed multipoint cummunications between terminals
- Describe series 2000 circuits
- used for voice transmission, can be used for half-duplex data. supports bandwidths of 300 hz to 3000hz.
- A TELPAK C channel is a grouping of 60 voice-grade channels and is available under which telephone company offering series
- 5000
- The switched network can guarantee accurate transmission of data at what maximum bps rate
- 4800
- What transmission method is more sophisicated and expensive
- synchronous
- How is Half-duplex different from full duplex
- Half-duplex allows for bidirectional transmission but not simultaneously
- What is simplex
- A communication channel that allows communication of information in one direction only
- The Parallel transmission mode is commonly referred as
- serial by character, parallel by bit