Chapter Questions
What are the three components common to all communications systems?
Define the terms marking and spacing with respect to the flow of current in a telegraph system.
Why is the telegraph considered to represent a binary state machine?
What is the term used to describe a transmission system capable of transmission in only one direction?
Discuss the difference between a half-duplex and full-duplex circuit with respect to their transmission support capability.
How does a telegraph operator inform a distant operator that they have data to send?
Discuss the method Morse used to assign codes to characters.
What is the International Morse code for HELLO?
What are the two key limitations associated with Morse code which precluded its use in automated telegraph operations?
Define a start element with respect to the signaling transition on a communications line. What is the significance of a start element?
What is the purpose of a stop element in start-stop signaling?
In start-stop communications, where is the timing information located when a character is transmitted?
What is the decimal value of the number $1011010_2$ ?
How did Baudot extend his five-level code to represent more than 32 characters?
Illustrate the marking and spacing conditions that define the character M in the Baudot code to include its start and stop bits.
What is the function of the diaphragm in a telephone transmitter?
If the period of a signal is 0.1 second what is its frequency in Hz ?
What is the function of tip and ring wires?
Discuss the relationship between an off-hook and on-hook condition, the circuit formed by tip and ring wires and the current flow in that circuit.
What is the purpose of a telephone slide tone?
Name two types of telephone dialing.
What is the primary function of a switchboard?
Assume that you are dialing a long distance telephone number. If you enter the dialing digits in the format I XXX YYY ZZZZ, what do the $1, \mathrm{XXX}$, YYY and ZZZZ digits represent?
Where is a telephone company end office located in PSTN switching hierarchy?
What is a point of presence?
What are two advantages associated with local loop bypass?
Assume you want to use a dial-around carrier whose access code is 1010543 to dial the telephone number 2125551212 . What string of digits do you dial?