Name __________________________ Review Questions
SCC CIS 29 Chapter 15 - Communicating Over Phone Lines
Instructor Paul Bryant Due April 29, 2000 - Turned in ____________, 2000
| # | Question | Answer | Reference |
| 1 | How is communication over phone lines both direct and virtual? Give an example of each. | ___________________________________________ | ______________ |
| 2 | Converting a digital signal to analog is called ____________________. Converting analog back to digital is called ___________________. | . | . |
| 3 | Communication in only one direction at a time is ________________ communication. Communication in both directions at the same time is __________________ communication. | . | . |
| 4 | Why is the maximum transmission rate of today's modems limited to 56.6 Kbps? | . | . |
| 5 | How does the V.34 standard differ from the V.90 standard? | . | . |
| 6 | What two standards does the V.90 standard replace? | . | . |
| 7 | What organization is responsible for setting telecommunications standards? | . | . |
| 8 | Name two standards that pertain to data compression. | . | . |
| 9 | Why is a modem required to support more than one standard for transmission speed? | . | . |
| 10 | Name two reasons why a 56K modem might not transmit data at its maximum rated speed. | . | . |
| 11 | What happens when the receiving modem finds that the checksum is incorrect during data transmission with error checking? | . | . |
| 12 | On external modems, what is the purpose of the TD and RD lights? | . | . |
| 13 | Describe the difference between port speed and modem speed. | . | . |
| 14 | What chip controls a serial port? | . | . |
| 15 | When an external modem connects to a PC, what port is normally used? Describe the shape and name of the port connection. | . | . |
| 16 | During data transmission, what two devices can initiate a flow control message? | . | . |
| 17 | Why is hardware flow control better than software flow control? | . | . |
| 18 | Which two pins on a 9-pin serial cable are used for hardware flow control? What are these two pins called? | . | . |
| 19 | Why is it best to not have the UART chip perform parity checking? | . | . |
| 20 | What company invented the AT command set for a PC to communicate with a modem? | . | . |
| 21 | What is a dial-up, digital data transmission technology that is faster than regular phone lines? | . | . |
| 22 | Name two data-transmission technologies that offer a direct, "always up" connection. | . | . |
| 23 | List three hardware reasons why a modem might not respond. | . | . |
| 24 | List three software reasons why a modem might not respond. | . | . |
| 25 | Which is faster, an ISDN line or an ADSL line? | . | . |
