DSL and ISDN

 

Although the standard equipment provided by telephone company limits the amount of data you can transmit and receive over a voiceband modem, the copper wire that runs from your wall jacks to the switching station actually has a fair amount of capacity. DSL and ISDN take advantage of this capacity to offer high-speed digital communication links for voice and data.

DSL (Digital Subscriber Line) is a high-speed, digital, always-on Internet access technology that runs over standard phone lines. It is one of the fastest Internet connections that are affordable to individual consumers. Several variations of this technology exist, including ADSL (asymmetric DSL, with downstream speed faster than upstream speed). DSL is digital, so data doesn’t need to be changed into analog form and then back to digital as it does when you use a dial-up connection.

A DSL connection can simultaneously carry voice and data, if permitted by your DSL provider. The digital data and analog voice signals travel over DSL line to the local switching station. There the voice signals are transferred to the telephone company’s regular lines.

The speed of a DSL connection varies according to the characteristics of your telephone line, the equipment at your local switch and your distance from the switching station.

ISDN (Integrated Services Digital Network) connections move data at speed that is not as fast as DSL or cable Internet service. As with DSL, ISDN is an all-digital service with the potential to simultaneously carry voice and data. A device called ISDN terminal adapter connects a computer to a telephone wall jack and translates the computer’s digital signals into signals that can travel over the ISDN connection. ISDN service is typically regarded as a high-speed Internet connection option for businesses that maintain small LANs.

 

Вариант 4

1 .Перепишите предложения, найдите в них инфинитив и подчеркните его, определите его форму. Письменно переведите предложения на русский язык.

 

1. To prevent intrusions, you need to take additional precautions.

2. The equipment to be installed is very effective.

3. Automatic Management Systems are known to have appeared quite recently.

4. The development of the project appears to be improving.

5. The first electronic computer is thought to have been constructed in 1946.

 

2. Перепишите предложения, подчеркните инфинитив и определите его функцию. Письменно переведите предложения на русский язык.

 

1. It is necessary to deactivate file and printer sharing if your computer is not

connected to LAN.

2. The first step is to make sure that operating systems security patches and service

packs are up to date.

3. Although many people begin with a dial-up connection, many soon prefer to

explore high-speed Internet access options.

4. Firewall software is designed to analyze and control incoming and outgoing

packets.

5. How would you like high-speed Internet access to require no cables, no modem and no more subscription fees?

 

3. Перепишите предложения. Подчеркните в каждом инфинитивный оборот и определите его форму (объектный, субъектный и предложный инфинитивный оборот). Письменно переведите предложения на русский язык.

 

1. For a computer to be programmed each problem must be reduced to a series of very simple steps.

2. A remote terminal enables the user to operate the distant computer, just as if that person were sitting in front of the distant computer and using its keyboard.

3. The event is a message that causes a procedure (subprogram) attached to

respond.

4. As your data arrives at the ISP, a router is likely to send it out over the

Internet.

5. When you transmit data, your modem is sure to modulate the signal that carries your data.

 

4. Преобразуйте предложения, воспользовавшись инфинитивом или инфинитивным оборотом и словами в скобках, если они даны. Письменно переведите полученные предложения на русский язык.

 

1. He said: “No smoking, drinking or eating at the computer”.

2. He was very inexperienced. He could not conduct an experiment of this type.

(too).

3. It is possible that computers can handle all types of information. (for)

4. He was the last man who left the office.

5. It is advisable that we should reboot the system if problems occur.

 

5. Перепишите предложения, употребив нужную форму прилагательного (much – many, (a)little – (a) few). Письменно переведите предложения на русский язык.

 

1. I haven’t given very… attention to this problem.

2. There are … … free ISPs who only charge local or national rates for their

telephone helplines.

3. …notebooks have built-in Wi-Fi transceivers and software.

4. Overseas transmission usually requires... …more time.

5. It takes… time to get documents via the mail but they arrive in minutes via

e- mail.

 

6. Прочтите и письменно переведите текст.