Cell phone transmitter and receiver and the host telephone base do not have the physical connection between a telephone. Handset and the connection is between the respective lowpower radio transmitter with replaced by. The host is still with the telephone network through the telephone line connected to the switch.The use of cordless phones users can [...]

System.If you want to find out a certain person with the pager as long as the use of local calls will be looking for those pager number a brief content and my phone number to operator the operator will record the information and a special signalissued through the radio transmitter then those who were paging [...]

Faster than GSM. 2G systems can not only provide various telephone services also provides short message services.Secondgeneration mobile communication system in the data transmission speed is far below the normal speed of the computer. Thirdgeneration 3G mobile communication systems is the development direction. May 2000 approved three ITU 3G standards: Japan and the European launch [...]

Original cell site received signal becomes weak the base station is requesting mobile telephone office switch. Mobile telephone office will be channel switching to a new channel on the plot the whole switching process is done automatically the time less than 1s the call will not be interrupted the user will not notice.The first generation [...]

Have the characteristics of the frequency reuse. For example China’s introduction of panEuropean GSM system base station transmitters 900MHz band 935 ~ 960MHz 800MHz band launch mobile station 890 ~ 915MHz each frequency band width of 25MHz. Also according to 200kHz band is divided into a number of channels also known as channels such channels [...]

Mobile phone. Cellular mobile telephone service area such as a city is divided into a number of adjacent hexagonal cell. Quarter side several hundred meters to ten kilometers each cell has a wireless base station. Base station is responsible for the district of mobile phone calls sent to mobile telephone services switching center ie mobile [...]

VSAT systems can direct line with the rest of the world by satellite data voice fax and other highspeed transmission.At present China Post and Telecommunications sector in addition to the common VSAT system a number of ministries or business has its own VSAT system constitutes a private communication network within the system. For example the [...]

Department 500km in the same orbit three satellites and 120 ° apart constitute the northern hemisphere high latitude regions of the fulltime coverage.Large highinclination elliptical orbit satellite communications to make up for the synchronous satellite communications in the high latitudes have blind spots deficiencies. But the satellite life expectancy was short only 3 to 4 [...]

Satellite and then to earth stations transmission distance big caller to hear each other’s answer at least half a second later. Second as the orbit plane and equatorial plane for the same plane be difficult to achieve high latitude satellite communications the Earth near the poles there are satellite communications blind spots.Synchronous satellite communications since [...]

Need three separated by 120 ° of the synchronous communications satellite. For example A earth station with the other parts of the earth station to communicate B A stops the microwave signal to the satellite the satellite will receive the signal amplification frequency conversion and other processing then forwarded to the B station then A [...]