Communication Connectors Classification and Application

The electrical connector allows current to be circulated in a circuit that is blocked or isolated, allowing the circuit to perform its intended function. Some connectors are made in the form of ordinary sockets and are widely recognized and used in the cable industry.

(Image from the internet)

The classification of electrical connectors has been confusing for many years, and each manufacturer has its own classification methods and standards. In 1989, the National Electronic Distributors Association (NEDA) presided over the development of a set of standards called "Levels of Packaging". According to this standard, communication connectors typically use a 4-level connector. But the level is only used to learn and classify the connector. In practice, the connector is rarely talked about according to the above level, but it is named according to the appearance of the connector and the structure of the connection (the name of the electrical connector of different structure is determined by Specific specifications are generally specified in the international general; in general, connectors of different structures have different application ranges). The connection of the communication network often depends on the media used, so the connectors are usually discussed in terms of different connection media, connections and applications.
1. Multi-wire cable connector
Multi-wire cable connectors include DB connectors and DIX connectors as well as DIN connectors.

1. DB type connector includes DB-9, DB-15, DB-25 connector, which is used to connect serial device and parallel cable, which is divided into male terminal and female terminal. DB in DB25 represents D connector. The number 25 represents the number of pins of the connector. The DB25 connector is a common device for current microcomputer and line interfaces.
2. DIX connector: its appearance is like a DB-15 connector. It is connected with a slider when it is connected, and the DB15 is fixed by screws when it is connected, and is often used to connect a thick cable Ethernet.
3. DIN connector: There are different pins and pin arrangement in the DIN connector, which is generally used in connection with Macintosh and AppleTalk networks.

2. Twisted pair connector
Twisted pair connection includes two types of connectors: RJ45 and RJ11.RJ are interfaces for describing the public telecommunication network. In the past 4 categories, 5 categories, 5 categories, and even 6 types of wiring, the RJ is used. Type interface.

1. RJ11 connector: It is a telephone line type connector that supports 2 lines and 4 lines, and is generally used for user telephone line access.
2. RJ45 connector: a connector of the same type, jack type, larger than the RJ11 connector, and supports 8 lines, is a common name for the standard 8-bit modular interface, and is mostly used for connecting twisted pairs in the network. . Since the circuits used are balanced transmitters and receivers, they have high common mode rejection.

3. Coaxial cable connector
The coaxial cable connector includes a T connector and a BNC connector and a terminating resistor.

1. T connector: used to connect coaxial cable and BNC connector.
2. BNC connector: BayoNette bayonet barrel connector for connecting the network segment to the BNC connector. The rapid growth of the communications and computer markets and the combination of communication technology and computer technology have become major factors in stimulating the growth in demand for coaxial connectors. Since the coaxial cable and the T-connector are connected by BNC connectors, the BNC connector market is optimistic for the industry.
3. Terminator: The cable requires a terminator. The terminator is a special type of connector. It has a carefully selected resistor that matches the characteristics of the network cable. Each terminator must be grounded.
4. The N-type connector is used in the thick cable Ethernet. The workstation is not directly connected to the Ethernet network. Instead, it is connected to the transceiver through an AUI connector (DIX connector) using a transceiver.

RF coaxial connectors are divided into the following types:

1. Threaded connection type: such as: APC-7, N, TNC, SMA, SMC, L27, L16, L12, L8, L6 and other RF coaxial connectors. This type of connector has the characteristics of high reliability and good shielding effect, so it is the most widely used.
2. Bayonet connection type: such as BNC, C, Q9, Q6 and other RF coaxial connectors. This connector has the characteristics of convenient and fast connection, and is also the earliest application form of RF connector in the world.
3. In-line push connection type: such as SMB, SSMB, MCX, etc., the connector of the connection form has the characteristics of simple structure, compactness, small size, and easy miniaturization. 

Serial communication is a widely used communication method. In serial communication, both parties to the communication are required to use a standard interface. 

The connectors of the ISDN basic interface are all based on the ISO8877 standard. The standard specifies that the S interface standard connector is RJ-45 (8 core), the middle 4 cores are effective cores; the U interface connectors are not standard, some manufacturers use RJ-11, and some use RJ-45, which are intermediate Two cores are effective. The connectors of the G.703 interface in the digital transmission network are generally BNC (75 Ω) or RJ-45 (120 Ω), and sometimes a 9-pin interface is also used. The USB specification (Universal Serial Bus) is a connection standard that provides a universal connector (Type A and Type B) for all USB peripherals connected to a PC. These connectors will replace traditional external ports such as serial ports, game interfaces, parallel ports, and more. 

In terms of integrated wiring, the previous four categories, five categories, and five categories, including the six types of wiring that have just been introduced, all use RJ type interfaces. Starting from the seven categories of standards, the division of RJ-type and non-RJ-type interfaces has appeared in the history of wiring. The Cat7 connector assembly (GG45-GP45) standard was unanimously adopted on March 22, 2002 (IEC60603-7-7), becoming a Category 7 standard connector and fully compatible with current RJ-45. 

The selection includes the use of environmental conditions, electrical parameters, mechanical parameters, and termination methods. Specifically, it includes electrical parameter requirements, rated voltage, rated current, contact resistance, shielding, safety parameters, mechanical parameters, mechanical life, connection method, installation method and shape, environmental parameters, termination methods, and so on. 

The development of electrical connectors has the following characteristics:

1. Develop in the direction of miniaturization, high density and high speed transmission;
2. Towards the development of high performance and high frequency technology;
3, high voltage, high current connector demand market is also very large;

4. The connector is also developing in the direction of anti-jamming technology, modular technology and lead-free technology. 

In the case where the rate of the conventional parallel synchronous digital signal is to reach the limit, the high-speed serial mode is a good solution. It makes low voltage differential signaling (LVDS) the primary level standard for next generation high speed signals. The choice of high-speed connectors has also become a major problem to be solved by high-speed signal interconnection.

Konnra Electronics has analyzed the classification and application of communication connectors for the majority of users. We hope that everyone can gain something after reading it. If there are other problems or different introductions, please contact us by email.