What is RJ45?

       RJ45 is a kind of information socket (ie communication terminal) connector in the wiring system. The connector consists of a plug (connector, crystal head) and a socket (module). The plug has 8 grooves and 8 contacts. RJ is the abbreviation of Registered Jack, which means "registered socket". In FCC (Federal Communications Commission Standards and Regulations), RJ is an interface describing public telecommunications networks, and RJ45 for computer networks is a common name for standard 8-bit modular interfaces.

1,Design principle

The RJ45 is composed of a plug and a socket. The connectors composed of these two components are connected between the wires to realize the electrical continuity of the wires.
The core of the RJ45 module is the modular jack. The gold-plated wire or socket hole can maintain a stable and reliable electrical connection with the modular socket shrapnel. Due to the friction between the shrapnel and the socket, the electrical contact is further strengthened as the plug is inserted. The main body of the jack is designed with an integral locking mechanism, so that when the modular plug is inserted, the interface between the plug and the jack can have the greatest pulling strength. The wiring module on the RJ45 module is connected to the twisted pair through the "U"-shaped wiring slot, and the locking spring can fix the RJ45 module on the information outlet device such as the panel.

2.Wire sequence connection

The information module or the RJ45 connecting plug and the twisted pair termination have two structures: T568A or T568B. In T568A, the 8 wires connected to it are defined as: white green, green; white orange, blue; white blue, orange; white brown, brown. In T568B, the 8 wires connected to it are defined as: white orange, orange; white green, blue; white blue, green; white brown, brown. The differential transmission lines defined are white-orange and orange cables, white-green and green cables, white-blue and blue cables, and white-brown and brown cables.
In order to achieve the best compatibility, the T568B standard is generally used when making a straight-through cable. The sequence number of the RJ45 crystal header pins should be observed as follows: Turn the front of the RJ45 plug (the side with the copper pins) toward you, the end with the copper pins upwards, and the end of the connecting cable downwards. Connect 8 copper pins from left to right. The needles are numbered from 1 to 8.

3.Performance indicator

The performance indicators of RJ45 also include attenuation, near-end crosstalk, insertion loss, return loss, and far-end crosstalk. Technical description of RJ45 performance: The contact resistance is 2.5mΩ, the insulation resistance is 1000mΩ, and the dielectric strength is DC1000V (AC700V), there will be no breakdown and arcing in one minute; the surface of the clip reed is gold-plated or silver-plated, and the wire diameter is available. It is 0.4mm～0.6mm; the number of plugs and sockets can be re-plugged not less than 750 times; 8-wire contact pin is gold-plated 509 (inch)
Among these performance index requirements, crosstalk is an important factor considered in the design. In order to make the entire link have better transmission performance, crosstalk cancellation technology is often used in sockets. Crosstalk cancellation technology can produce the same amount of interference as the interference introduced from the plug. , Crosstalk signals of opposite polarity to cancel crosstalk. If the crosstalk interference introduced by the modular plug is represented by "++++", the opposite crosstalk generated by the socket is represented by "----". When the two crosstalk signals are equal in size and opposite in polarity, the total coupled crosstalk interference signal is zero.

 

 

 

How far(long) the transmitter cover? The transmission range depends on many factors. The true distance is based on the antenna installing height , antenna gain, using environment like building and other obstructions , sensitivity of the receiver, antenna of the receiver . Installing antenna more high and using in the countryside , the distance will much more far. EXAMPLE 5W FM Transmitter use in the city and hometown: I have a USA customer use 5W fm transmitter with GP antenna in his hometown ,and he test it with a car, it cover 10km(6.21mile). I test the 5W fm transmitter with GP antenna in my hometown ,it cover about 2km(1.24mile). I test the 5W fm transmitter with GP antenna in Guangzhou city ,it cover about only 300meter(984ft). Below are the approximate range of different power FM Transmitters. ( The range is diameter ) 0.1W ~ 5W FM Transmitter ：100M ~1KM 5W ~15W FM Ttransmitter : 1KM ~ 3KM 15W ~ 80W FM Transmitter : 3KM ~10KM 80W ~500W FM Transmitter : 10KM ~30KM 500W ~1000W FM Transmitter : 30KM ~ 50KM 1KW ~ 2KW FM Transmitter : 50KM ~100KM 2KW ~5KW FM Transmitter : 100KM ~150KM 5KW ~10KW FM Transmitter : 150KM ~200KM How to contact us for the transmitter? Call me +8618078869184 OR Email me [email protected] 1.How far you want to cover in diameter ? 2.How tall of you tower ? 3.Where are you from ? And we will give you more professional advice. About Us FMUSER.ORG is a system integration company focusing on RF wireless transmission / studio video audio equipment / streaming and data processing .We are providing everything from advice and consultancy through rack integration to installation, commissioning and training.   We offer FM Transmitter, Analog TV Transmitter, Digital TV transmitter, VHF UHF Transmitter, Antennas, Coaxial Cable Connectors, STL, On Air Processing, Broadcast Products for the Studio, RF Signal Monitoring, RDS Encoders, Audio Processors and Remote Site Control Units, IPTV Products, Video / Audio Encoder / Decoder, designed to meet the needs of both large international broadcast networks and small private stations alike.   Our solution has FM Radio Station / Analog TV Station / Digital TV Station / Audio Video Studio Equipment / Studio Transmitter Link / Transmitter Telemetry System / Hotel TV System / IPTV Live Broadcasting / Streaming Live Broadcast / Video Conference / CATV Broadcasting system.   We are using advanced technology products for all the systems, because we know the high reliability and high performance are so important for the system and solution . At the same time we also have to make sure our products system with a very reasonable price.   We have customers of public and commercial broadcasters, telecom operators and regulation authorities , and we also offer solution and products to many hundreds of smaller, local and community broadcasters .   FMUSER.ORG has been exporting more than 15 years and have clients all over the world. With 13 years experience in this field ,we have a professional team to solve customer's all kinds of problems. We dedicated in supplying the extremely reasonable pricing of professional products & services. Contact email : [email protected] Our Factory We have modernization of the factory . You are welcome to visit our factory when you come to China. At present , there are already 1095 customers around the world visited our Guangzhou Tianhe office . If you come to China , you are welcome to visit us . 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