what area does two way radio mainly use for?
Two way radio is mainly used in public security, civil aviation, transportation, water conservancy, railway, manufacturing, construction and service industries. It is used for communication and command dispatch among group members to improve the efficiency of communication and improve the rapid response ability of dealing with emergencies. More and more people begin to use two way radio in travel, shopping after two way radio used in the civilian market.
Regular maintenance of two way radio
1.     Your two way radio maybe dirty after long-term used, especially the keypad, knob and radio body. Please remove the knob and clean with a mild detergent (Do not use strong corrosive chemicals). Clean the cabinet with a damp cloth. The use of chemicals such as detergents, alcohol, sprays or petroleum preparations may cause damage to the surface and enclosure of the two way radio.
2.     Handle gently, do not move the walkie-talkie by hand-held antenna.
3.     Please cover the radio with dust cover (if equipped) if you don’t use it.
Use safety precautions
1.     Do not put the radio on the airbag deployment may be involved in the range while you are in a car with airbags. If the radio is in the airbag deployment may involve the scope of the region, once the airbag to expand rapidly, walkie-talkie may be a great impact with the injury inside the car. If the radio is in the airbag deployment may involve the scope of the region, once the airbag to expand rapidly, walkie-talkie may be a great impact with the injury inside the car.
2.     Turn off the radio in a potentially explosive atmosphere or occasion, unless the walkie-talkie is through special authentication. In potentially explosive atmospheres, electrical sparks can cause an explosion or fire.
3.     Do not replace or charge the battery in potentially explosive atmospheres. Installation and removal of the battery may result in contact with the spark and cause an explosion.
4.     You must turn off the radio firstly, before near the blasting area and detonator in the area, so as not to cause a possible explosion.
Note on radio operation
1.     While the radio is transmitting, keep the radio in a vertical position, and keep the microphone 2.5-5 cm distance away from the mouth, at least 2.5 cm away from the head or body, at least 2.5 cm away from the human body.
2.     Do not switch off/on quite often while using, while adjusting the volume to fit your listening volume.
Precautions for battery use
1.     Use the original or approved battery.
2.     If the metal conductor such as jewelry, keys or beads touched the exposed electrodes of the battery, all batteries may cause damage or personal injury. Use caution when handling a charged battery, especially when handling it in a pocket, wallet, or other metal container.
3.     The charge should be 5 to 40 degrees in the environment. If this temperature range is exceeded, the battery life is affected, and it is possible to charge less than the rated capacity.
Precautions for Antenna Use
1.     Only use the original or approved antenna. Unauthorized antennas, modified or supplemented antennas may damage the radio or violate regulations of the Radio Regulatory Authority of the Ministry of Information Industry.
2.     Do not get the antenna by hand while using
3.     The radio antenna can’t be screwed off while using, or in the launch of the power tube is easy to burn out.
4.     Do not use the damaged antenna. While transmitting, if the damaged antenna touches the skin, it may cause minor burns.
Electromagnetic Interference / Electromagnetic Compatibility
To avoid problems caused by electromagnetic interference and / or electromagnetic compatibility, turn off the radio in the case of a "closed radio" logo. Such as hospitals or other occasions where health care medical equipment is used. In the plane, should also be required to turn off the radio.
Introduction to Digital Clustering
Digital cluster mobile communication system is a new generation of advanced professional radio command and dispatch system developed in the early 90s of the 20th century. Based on the analog cluster mobile communication system, the digital cluster mobile communication system adopts the most advanced digital technology and communication technology, which has the characteristics of advanced technology, high spectrum utilization rate and high data transmission rate. It integrates command and dispatch, telephone Interconnection, data transmission and short message communication and other advantages in one of the new generation of cluster communication technology. Digital cluster communication system is a dedicated command and dispatch system, the system channel using dynamic allocation, work for the simple and half-duplex mode, the network coverage area coverage, business focused on short-term wireless to wireless calls, business Users with priority and special features for group users and special user groups, belonging to the private network communication system. Digital cluster communication is developed on the basis of analog cluster communication. Digital cluster communication adopts digital processing in various key technologies such as signaling, multiple access mode, speech coding, modulation and demodulation, and channel control. Meanwhile, based on digital system, Features Combined with synchronization technology, error detection and error correction technology and diversity technology, the digital trunk communication with anti-interference ability, high-quality long-distance transmission, high security, high reliability and highly flexible service adaptability and peripheral interface connection Capacity, and other special features, and the entire digital cluster communication system capacity larger, more convenient system networking. Compared with the public network of the cellular mobile communication system, the professional network of the digital trunked mobile communication system emphasizes such functions as group call, general call, emergency call, forced disarming and different call priority levels; more emphasis on shortening the call establishment Time, especially in emergencies, hoping that a pass that is (less than 0.5s), otherwise it will cause very serious consequences; scheduling command requirements concise, the general talk time of tens of seconds. With the development of mobile communication technology, TETRA digital cluster mobile communication system has been developed under the background of the development of professional mobile communication system which can meet the demands of many different professional departments as much as possible.
Introduction to TETRA Technology
TETRA digital cluster mobile communication system is a kind of digital time division multiple access (TDMA) technology based wireless cluster mobile communication system. The system is a joint system of the ETSI (European Telecommunications Standards Association), manufacturers, testing departments and government departments, in order to meet the professional needs of European countries, the design of mobile communications, the development of a unified standard open system. TETRA digital cluster communication system can provide command dispatch, data transmission and telephone service on the same technology platform, it not only provides multi-group scheduling function, but also can provide short data information service, packet data service and digital full-duplex mobile phone service. TETRA digital trunked mobile communication system also supports a powerful mobile off-line through (DMO) approach, enabling authentication, air interface encryption and end-to-end encryption. TETRA digital trunked mobile communication system also has a virtual private network VPN function, you can make a physical network for multiple organizations are not related to service. TETRA digital cluster mobile communication system has abundant service functions, higher frequency utilization, high communication quality and flexible networking mode. Many new applications (such as vehicle positioning, image transmission, mobile Internet, database query) In the TETRA be achieved.
TETRA business functions
Wireless interface features Traffic channel is busy, the signaling channel can be used as a business letter to the use of base station failure weakening function Virtual private network authentication Air interface encryption End-to-end encryption Direct work mode Fast call establishment
TETRA business type
Basic service Subscriber service (single call, group call, telephone interconnection service) Bearer service (circuit mode data service, short data service, packet data service) Basic supplementary service Call type selection (single call, group call, Call) Area selection Priority call Preemptive priority call Late entry Dynamic reassembly Automatic retransmission Time-out call Out-of-service area indication Call display Caller / called party Display caller identification Caller identification display Unconditional call forwarding Busy call forwarding User can’t answer in time Transfer Non-Acknowledgment Transfer Abbreviated Addressing Dialing to a busy subscriber Completing a call to an unanswered call Completing a call barring Optional supplementary service station Verification Call screening Intercepting control Transfer billing
Technical terms
MONITOR
A listening mode to accept the weak signal using. Press the dedicated key to force the receiver signal channel, the operator with the ear to identify the faint sound of the speaker, to listen to the purpose.
Scanning (SCAN)
In order to hear all the channels of the call, and used a listening mode. By pressing the dedicated key, the receiving circuit in a certain order by a channel to receive a period of time to listen to the signal in the channel. If the time for each channel to receive 100ms, you can scan ten channels per second, the scanning speed of 10ch / s.
Priority Channel Scan
The set priority channel is preferentially scanned during scanning.
Delete / Add Scan Channel
Remove a channel from the scan list or add it to the scan list.
Voice-activated (VOX)
When the function is activated, you do not have to press the PTT button to start the transmission directly through the voice.
Time Out Timer (TOT)
This feature is used to limit the user in a channel over time transmission, but also to avoid long-time radio launch and cause damage.
Power saving function (Battery Save)
In order to save electricity, extend the standby time, the radio in a period of time without launch acceptance and key operation, will be shut down for some time, a period of time to start the work, this approach is called power saving. The switch-on time is approximately 1: 4. When receiving a signal or a key operation, the radio immediately exit the power-saving state, into the normal state.
High and low power select function (High / Low power)
This feature allows the user to select either high or low power depending on the situation.
Disable feature (Busy Channel Lockout)
When using this function, the user is prohibited from transmitting signals on a busy channel.
Squelch Level
The intensity of the noise in the received signal is corresponding to the strength of the signal, the stronger the signal is, the weaker the noise is. The maximum noise and minimum noise is divided into several files, each file is called a level. The files called squelch level. Users can choose according to the actual situation.

CTCSS / CDCSS functions
Use this feature to avoid receiving irrelevant calls.
2-TONE / DTMF selective call function
Use 2-TONE or DTMF signaling to select the appropriate intercom.
Reverse Frequency Function
When using the scrambling function, the transmission frequency and reception frequency of the radio are interchanged, and the set signaling is also interchanged.
Off-line function (Talk Around)
When the off-line function is used, the transmission frequency of the radio becomes the same as the reception frequency; the transmission signaling is also converted into the same as the reception signaling.
Auto-answer function (Auto-Transpond)
When the transceiver receives a correctly coded call, it sends a signal to the caller in response to the call.
Emergency Alarm (Emergency Alarm)
Press the special alarm key, the intercom to the maximum sound alarm or issue a predetermined alarm code to the other handset or base station.
Patrol Record
Patrol officers arrived at the patrol point, the radio will receive a patrol register issued by the query signal, and then automatically start the registration operation, the identity code and other information sent to the patrol register to be registered, indicating that a patrol has reached the place.
Key lock function
Use this function to prevent key error operation.
Battery Indicator
It shows the electric quantity.
Lighting function (Backlight)
For night or dim operation, you can see the LCD display and buttons.
Copy function (Cloning)
This feature allows data from one radio to be copied to other radios of the same model.
Modulation
Modulated signal with one or a few parameters to control the carrier parameters of the change, in accordance with the different control parameters, modulation can be divided into AM, FM and phase modulation.
Audio
Audio, refers to the human voice frequency, usually refers to 300Hz-3400Hz frequency band.
Carrier
Voice, digital signals and other useful signal carrier, easy to transmit high-frequency electromagnetic waves. Modulation signal with one or several parameters to control the carrier parameters of the change, in accordance with the different control parameters, modulation can be divided into AM, FM and phase modulation.
Channel and channel spacing
Channel refers to the frequency value occupied by transmitting and receiving. The frequency difference between adjacent channels is called the channel spacing. The prescribed channel spacing is 25 kHz (wide band), 20 kHz, 12.5 kHz (narrow band), and so on.
2-TONE
2-TONE, two tone signaling, composed of two audio signals, A Tone + B Tone. Start A Tone for a period of time, and then interval of time, then B Tone. The use of 2-TONE signaling can choose to call the corresponding walkie-talkie.
5-TONE
5-TONE, 5 tone signaling, the role of signaling with the same two, the difference is that the composition of the five frequencies.
CTCSS
CTCSS (Continuous Tone Controlled Squelch System), continuous voice control squelch system, commonly known as sub-audio, is a lower frequency than the audio frequency (67Hz-250.3Hz) attached to the audio signal transmission technology together. Because its frequency range below the standard audio, so called sub-audio. When the intercom for the received signal IF demodulation, the sub-audio signal through filtering, shaping, input to the CPU, and the machine set the CTCSS frequency to compare, to decide whether to turn on the mute.
CDCSS
CDCSS (Continuous Digital Controlled Squelch System), continuous digital control squelch system, its role and CTCSS the same, the difference is that it is a digital encoding as a mute is turned on condition.
DTMF
DTMF (Dual Tone Multiple Frequency), dual tone multi-frequency, by the high frequency group and low frequency group, high and low frequency group contains four frequencies. A high-frequency signal and a low-frequency signal superimposed to form a combined signal, representing a number. DTMF signaling has 16 codes. DTMF signaling can be used to select the appropriate call radio.