Ex.6 Answer the following questions

Modems

A modem is a device that converts digital data originating from a terminal or computer, to analog signals used by voice communication networks such as the telephone system. At one end, modems convert the digital pulses to audible tones and convert audio tones back to digital pulses at the other.

The word "Modem" stands for " MO dulator- DEM odulator".

Some of the modem characteristics are the following:

· Transmission speed. Modems are available in different transmission speeds, which are measured in BPS (bits per second) also called BAUD rate. Standard modems speeds: 9600 baud, 14400 baud, 28800 baud, 33600 baud, 56800 baud.

· Internal/External. Internal modems are electronic cards. An internal modem is installed in one of the computer's expansion slot. The external modem is connected to a computer using a serial cable to one of the computer's serial ports, and draws power from an external power source.

· Error detection and correction. Nowadays most of the modems support advanced error detection protocols at the hardware level.

· Compression. Most modems support a variety of data compression protocols. Using these protocols, the data throughput can rise by an average of 50%.

1. Do repeaters act as a filter to restrict the flow of problem traffic?

2. Can hubs be different? What kinds of hubs do you know?

3. What is the reason for traffic bottlenecks?

4. Can bridges be used to link unlike network segments such as Ethernet and Token Ring?

5. What do routers forward between networks?

6. What features does a brouter combine?

7. What is measured in BPS (bits per second)?

Ex.7 Make up all possible combinations:

network data transmission modem internal expansion electronic external serial power error hardware destination

segment modem slot cable port source detection correction level throughput card speed packet

Ex.8 Comment on the rules of word-building:

Regenerate, dissimilar, decision, unlike, nonroutable, manageable, expansion, available, compression, detection, correction, destination, audible.

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