A telephone is a communication tool that can transmit voice, and it is one of the most important means of communication in modern times. Although mobile phones have become mainstream communication devices, they still occupy an irreplaceable position in daily life and work. So what is the principle of the telephone? How to adjust the volume of the phone? How to install the telephone? Let’s take a look at the telephone knowledge encyclopedia!
1 Introduction to Telephone
Telephone [English: Telephone, from Greek τ?λε (tēle, meaning “far”) and φων? (phōnē, meaning “sound”), the old translation of telephony] is a long-distance communication device that can transmit and receive sound. As early as the 18th century in Europe, the word “telephone” was used to refer to a microphone connected by a wire (a cup connected by a wire). The emergence of the telephone is attributed to Alexander Graham Bell. The principle of the early telephone is that the voice of speech is a composite vibration in the air, which can be transmitted to a solid body, and is transmitted to a conductive metal by an electric pulse.
The improvement and invention of telephone in history include: toner microphone, manual exchange board, dial pad, automatic telephone exchange, program-controlled telephone exchange, dual-tone multi-frequency dialing, voice digital sampling, etc. New technologies in recent years include, ISDN, DSL, Internet telephony, analog mobile phones and digital mobile phones.
The industry is generally divided into telephone equipment manufacturers and telephone network operators. Historically, network operators have often had national monopolies. In recent years, with the opening and integration of the global telecommunication market and the development of technology, a situation in which multiple operators are competing in the same market has gradually emerged.
2 Principles of Telephone
Telephone communication is a communication technology that converts sound energy and electrical energy, and uses the medium of “electricity” to transmit language. The simplest form for two users to communicate is to connect two telephones with a pair of lines.
When the speaker picks up the phone and speaks into the microphone, the vibration of the vocal cords excites the air to vibrate, forming sound waves.
A sound wave acts on the microphone to generate a current, which is called voice current.
The voice current is sent along the line to the receiver of the other party’s telephone.
The function of the receiver is just the opposite of that of the transmitter – the current is converted into sound waves and transmitted to the human ear through the air.
In this way, the simplest call process is completed.
3 Basic structure of landline
A telephone is a terminal device that transmits voice in both directions through electrical signals.
The improvement and invention of telephones in history include: toner microphone, telephone manual exchange board, dial pad, automatic telephone exchange, program-controlled telephone exchange, dual-tone multi-frequency dialing, voice digital sampling and so on. New technologies include, ISDN, DSL, analog mobile phones and digital mobile phones.
Basic keys: telephone power cord, telephone line, take-up switch, receiver, booster button, microphone, local number chip, ringtone and speakerphone, memory code key, memory number chip, Numeric keys, memory retrieval key, memory storage key, redial key, working indicator light, hands-free key, R key, hands-free microphone, ringtone adjustment switch, P/T switch, hands-free reception volume adjustment knob.
4 Classification of telephones
1, wired telephones
The telephone has the function of converting the sound waves of the terminal into electronic signals, The telephone line is transmitted to the remote party, and at the same time, the electronic signal transmitted by the other party is regenerated into voice (sound wave), the function of making a call, and the function of sending a signal (dial pulse) that can be selected from multiple parties to notify the other party of the call sound and other functions. A telephone consists of a transmitter that converts voice into electric current and sends it to a telephone line, a receiver that restores the current sent by the other party to voice, a dial or button to call the other party, a ringtone that sends a calling tone, and the connection of these to the telephone line. Its function is composed of line network and so on. Inside the phone is a small box filled with carbon particles, with a thin duralumin vibrating plate in front of it. The vibrating plate vibrates according to the voice, vibrating the carbon particles, and the carbon particles conduct electric current. With the contact degree of the particles, the resistance changes and the voice current is generated. After the receiver receives the voice current of the other party, a magnetic force caused by the voice current is generated on the coil, and the iron vibrating plate vibrates to make a sound.
2. Cordless Phones
Wireless Loop-Cordless Phones Digital Cordless Phones
Analog Cordless Phones
Mobile phones
PHS (wireless phones)
3. Smart phones
With the development of IT technology With the continuous rapid development, the processing capability of embedded terminal equipment is getting stronger and stronger. At the beginning of this century, a telephone “smart phone” with a personal data assistant (PDA) appeared.
In addition to the complete fixed phone functions, smart phones usually also have large-capacity business card management functions, incoming and outgoing call management functions, preventing telephone harassment (telephone firewall) functions, and corporate group telephone business cards (internal business cards). ) management functions, as well as many functions of auxiliary office, such as: schedule, notes, calendar, calculator and other functions. Early smart phones had certain information exchange capabilities through dial-up Internet access, and realized the functions of sending short messages and receiving text messages. With the development of fixed-line smart phones in China in the past ten years, their processing capabilities have been strengthened, and the functions of smart phones have gradually increased.
Smart phones have the ability to access the Internet through the Internet and strong multimedia functions. It can browse the Internet, play audio and video, and have functions such as e-books and electronic photo frames. At the same time, the functions of smart phones in auxiliary office, auxiliary marketing and entertainment have also been greatly strengthened. On the basis of subverting the traditional fixed telephone, more business functions and PDA functions have been realized.
5 Purchase of telephone landline
1. Choose a telephone that is compatible with the local exchange system
1. If the local area is a program-controlled telephone office , the user should choose the dual-tone key telephone, which is convenient for the user to use the new functions of the program-controlled telephone.
2. If the local telephone office is an electromechanical exchange, the user can choose a dial-type telephone or a pulse-type key telephone.
3. If there is a local program-controlled telephone office and an electromechanical switchboard, the user can choose a telephone with dual-tone and pulse-type dual dialing functions. (There is a “P/T” switch on this phone, dial to the “P” end, it is suitable for the electromechanical telephone office, dial to the “T” end, you can use the dual tone dialing method).
2. Selection of multifunctional telephones
1. Hands-free speaker function: It is suitable for people who want to make calls without picking up the handset (press the Raise the key SPEAK-ER), or multiple people can answer the incoming call together.
2. LCD display function: It is suitable for users who often use long-distance direct dial telephones. Because long-distance calls have many digits at one time, it is easy to dial wrong numbers. Time also benefits.
3. Recording and answering function: suitable for users who are busy with work and often go out.
4. Phone number storage function: It can save the time of dialing and checking numbers.
5. Others: There are also security functions (PRIVACY) and automatic redial functions (REDI-AL).
Three. Quality inspection before purchase
1. Appearance quality inspection: the plastic shell should be smooth and without cracks; it should be placed on the table smoothly; shaken There should be no sound of loose parts when the phone is in use; the hook and buttons of the phone are flexible and bounce freely; the cord socket of the phone should not be loose, and the cord should not have the phenomenon of plastic aging and hardening.
2. Sound check: After the line is connected, check whether the ringing tone, the voice of the voice and the voice of the received voice are clear, and there should be no sharp whistling and noise.
3. Function check: Check the main functions of the telephone item by item. For example, check whether there is obvious distortion in the tones coming out of the speakers, etc.
6 How to install a landline phone
1. Installation of a landline phone
The first step of installing a landline phone Choose a junction box, preferably close to the user, it will be more convenient. Then select a numbered line, each user will usually have one wiring, that is, select it in the line marked with the number. Then, pull a line from the outside of the junction box to the inside of the house. If this line is RJ-11, it is connected to the phone used for testing. At this time, you can dial 111## to check whether it is this number. Next, find a port in the outside line, and then use a special jumper to connect a port on the inside line to the port on the outside line. The last step is to plug the fuse unit into the external port.
2. Main matters of telephone installation
A fixed telephone is a commonly used communication tool, and there are some precautions in the installation process. First of all, when installing the landline, try to keep it away from the light line to prevent the risk of electric shock. Also, don’t lean against doors and windows to avoid wind and rain from causing dust in the phone to accumulate and cause rust and mold on the internal parts of the phone. Also, it is best not to install it in the kitchen to avoid moisture and dust on the wiring.
7 Telephone failure maintenance
1. The power indicator light is off
1. The fuse is blown, and the voltage has no output. Replace the fuse. Can.
2. If the indicator light fails, the machine can work normally.
3. The machine cannot work normally, and the power supply part is faulty.
2. There is no sound when the single extension phone is lifted
1. The indicator light of the extension user board is off, and the extension lead line is broken.
2. The extension user board indicator light is on, and the extension lead wire is short-circuited.
3. The telephone is faulty.
4. The extension circuit of the user board is damaged.
3. Noise from the extension phone when picking up the phone
1. When all the phones are noisy, check the power supply voltage and the grounding of the switch.
2. When a single unit is allowed to check the noise, check whether the extension phone and extension line are grounded or crossed.
3. The extension circuit of the switch user board is faulty.
Fourth, the extension does not ring, you can call and talk
1. A single phone does not ring: a phone is faulty. b The contact of the ringing relay of the extension circuit is closed, and it cannot jump up normally. It can be restored by tapping the relay on the user board with your finger.
2. All extensions do not ring: a The internal ringing circuit of the power box is faulty and needs to be repaired by a special person. b The ringing current power output line is in poor contact with the motherboard, and it can be restored after replaying the power after power off.
