MEANS OF COMMUNICATION experthow com What are they

MEANS OF COMMUNICATION experthow. com

What are they? What do you know about them?

The telegraph Strip of paper button source of electricity tecno 12 -18. com electromagnet mitter trans receiver

HOW DOES THE TELEGRAPH WORK? 1. The button is activated. 2. The current passes through the channel 3. The electromagnet recieves the signal and moves a pointer. 4. The pointer draws points and lines.

TELEGRAM: It is the sent or received message through the telegraph metroposdcard. com

The telephone handset receiver Switch hook Feature buttons microphone Dialling pad Hanset cord console Tecno 12 -18. com Telephone cable

How does the telephone work? 1. 2. 3. Transformation of the sound into an electrical signal. Transportation of the signal. Regeneration of the sound from the electrical signal. www. antiquetelephonehistory. com/images/telewo. . .

RADIO • Electromagnetic wave • “carrier waves” amplitude modulation (AM) radio frequency modulation (FM)

RADIO TRANSMISSION DIAGRAM qwickstep. com

The TV camera • The TV camera turns a picture and sound into a signal • How does the camera work? 1. Lens 2. Semiconductor material 3. Beam of electrons

The TV receiver A: Cathode B: Conductive coating C: Anode D: Phosphor coated screen E: electron beams F: Shadow mask

How does the TV receiver work? 1. The TV camera turns a picture and sound into a signal 2. The TV transmitter sends the signal through the air. 3. The TV receiver captures the signal and turns it back into picture and sound.

THE INTERNET • It is a global network connecting millions of computers. • KEY VOCABULARY: 1. Modem: It connects a the computer to the telephone line. 2. Browser: It displays web pages on the computer screen. 3. www(world wide web): collection of multimedia web pages that can be displayed using a browser. www. microsoft. com/. . . /68573 -router-diagram. gif

HOW DOES THE INTERNET WORK? consumer. hughesnet. com/img/howitworks. gif