Best RJ45 Keystone Jack: 8 Must-know Facts

Dec 18, 2024

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RJ45 keystone jack is also called keystone modules.This article will analyze the technical specifications of the best rj45 keystone jack used in network cables, we will focus on 8 must-know facts about the best RJ45 keystone jack, and introduce its functions, applications,classifications, compositions,phosphor bronze,gold pins,materials and how to judge the quality.

We are probably familiar with RJ45 connectors, as many people who are not in the cabling business can easily make a network cable connection with an RJ45 plug. However, RJ45 keystone jacks may be less familiar. In fact, keystone jacks are a crucial part of network systems, playing a key role in achieving stable and efficient network connections. A standard RJ45 keystone jack looks like the one shown below.

A standard RJ45 keystone jack

You might feel both familiar and unfamiliar with RJ45 keystone jacks; isn't it just the female counterpart of the RJ45 connector? You can think of it that way. RJ45 keystone jacks are widely used in networks. For example, you might have seen this type of keystone jack faceplate in your office. It is also used in home renovations.

You may also see network patch panels in many internet data centers, like the one shown below.

network patch panels in many internet data centers

A RJ45 keystone jack is a hardware component used to connect such computer network devices. It typically includes one or more network interfaces that allow computers or other devices to connect to a local area network (LAN) or wide area network (WAN). The main function of a keystone jack is to provide network connectivity and data transmission, enabling devices to communicate with other network devices and share resources.

Keystone jacks are widely used in various Ethernet networks, including CAT5, CAT5E, CAT6, and CAT7 cables. It is a standardized interface that provides reliable and high-speed data transmission, enabling effective communication and data exchange between network devices.

In the early days of network server rooms, network patch panels were more common. The purpose of a network patch panel is to organize the external network cables that converge in the server room, which are often disorderly. If you want to connect them to a switch in a logical order, it is very difficult. By first attaching the disorderly cables to a patch panel and marking them, and then connecting the patch panel to the switch with patch cables, the logical order can be clarified, making it very neat and easy to adjust. Patch panels are equipped with marking cards that indicate the wire sequence. We attach the pre-wired cables to the back of the patch panel and mark them on the front, making it very scientific and easy to manage when connecting to the ethernet switch. Of course, many server rooms now also use external connection labels on the returned cables, which is another management method.

Patch panels are equipped with marking cards that indicate the wire sequence. We attach the pre-wired cables to the back of the patch panel and mark them on the front, making it very scientific and easy to manage

The RJ45 keystone jacks we usually refer to are 8P8C RJ45-type keystone jack sockets. There are also other types, such as those used in telephone systems and fax machines, which differ in the number of wire cores they can support inside the socket and the connector. The RJ45 connector we often use is also known as 8P8C. The internal structure of an 8P8C connector or socket consists of 8 positions (Position) and 8 contact points (Contact), which are the metal connection points. Each contact point corresponds to a wire core of the network cable. Our data network cables have 8 cores, which correspond perfectly. This 8P8C structure ensures stable network connections and data transmission, enabling high-speed network support.

8P8C RJ45-type keystone jack sockets

Besides the 8P8C RJ45-type connectors or keystone jacks, there are many other types. RJ10 - a simple 4P4C rectangular connector for telephone handsets. RJ11 - a 6P2C or 6P4C square connector used to connect modems and telephone lines. RJ12 - the same size as RJ11 but with 6P6C. RJ14 - 6P4C, with two lines, can connect two phones or modems. RJ21 - a modular connector with up to 50 contact points, used to connect up to 25 circuits in large telephone systems.

6P4C 6P6C and 6P2C Plugs and keystone jacks

This article will focus on the 8P8C RJ45 keystone jack, and other types of keystone jacks will not be discussed here.

4P4C and 4P2C Plugs and keystone jacks

RJ45 keystone jacks can also be classified based on whether they have shielding capabilities, simply divided into unshielded and shielded types. Unshielded RJ45 keystone jacks are the most common type, with a simple structure and low cost, suitable for environments with low electromagnetic shielding requirements, such as general home and office settings. Shielded RJ45 keystone jacks, on the other hand, have better anti-interference and electromagnetic protection capabilities, making them widely used in environments with high requirements for signal transmission quality and data security, such as finance, healthcare, and military applications.

Unshielded RJ45 keystone jacks are the most common type, with a simple structure and low cost, suitable for environments with low electromagnetic shielding requirements,

Unshielded keystone jacks are easy to identify; those with an environmentally friendly PC material outer shell are unshielded. This is also the most common type of RJ45 keystone jack we see.

Keystone jacks with PC material outer shell are all unshielded keystone modules

The shielding method of shielded RJ45 keystone jacks is similar to that of shielded RJ45 plugs; a metal shielding layer is wrapped around the outer periphery, effectively reducing the impact of external interference on signal transmission and improving the stability and accuracy of data transmission. Shielded RJ45 keystone jacks can also prevent the leakage of their own electromagnetic signals, protecting user data security. Although the appearance of shielded RJ45 keystone jacks is no different from that of unshielded ones, their role in practical use is very important.

RJ45 keystone jacks is similar to that of shielded RJ45 plugs; has a metal shielding layer is wrapped around the outer periphery

There are also shielded RJ45 keystone jacks that are directly placed on network faceplates.

shielded RJ45 keystone jacks that are directly placed on network faceplates

In addition to the classification by internal structure and shielding methods introduced in the previous article, RJ45 keystone jacks can also be classified by wiring methods. If we look at keystone jacks, we can see that there are keystone modules that are tool-free and others that require on-site wiring.

there are keystone modules that are tool-free and others that require on-site wiring.

The latter involves using a crimping tool to insert each core of the network cable into the corresponding slot according to the TIA568A or 568B wiring sequence and securing it firmly. Each slot is connected to the metal connection points at the front of the RJ45 keystone jack. This integration allows the RJ45 keystone jack socket to seamlessly connect with the network cable. Each metal strip in the socket is connected to each core of the network cable.

The latter involves using a crimping tool to insert each core of the network cable into the corresponding slot according to the TIA568A or 568B wiring sequence and securing it firmly.

Tool-free keystone jacks come with built-in wiring terminals, eliminating the need for a crimping tool. The eight cores of the network cable can be directly placed into each slot and secured by pressing.

Tool-free RJ45 keystone jacks are more commonly used in current network cabling due to their advantages: better flexibility, easier installation, and greater scalability and flexibility due to their plug-and-play design. However, many installers still prefer wired keystone jacks for their stable signal transmission, as the contact points are more stable. However, wired module installation is more complex and requires professional skills.

568B and 568A wiring method of the toolless keystone jacks

When introducing network cables, we mentioned that they can be classified as CAT5E, CAT6, CAT7, CAT8, etc., based on their operating frequency and transmission performance.

network cables can be classified as CAT5E, CAT6, CAT7, CAT8, etc., based on their operating frequency and transmission performance.

The higher the transmission rate, the thicker the wire cores to ensure they can carry more network signals, which requires corresponding connectors to be differentiated. RJ45 plugs are differentiated, so are keystone jacks.

The higher the transmission rate, the thicker the wire cores to ensure they can carry more network signals, which requires corresponding connectors to be differentiated.

Most RJ45 keystone jacks are labeled on their housing, such as CAT5e for Category 5e, and CAT6 for Cat 6.

The difference between CAT5E and CAT6 is in the craftsmanship and thickness of the internal metal strips. In CAT7 and CAT8 jacks, gold plating is added to the metal strips to enhance signal conductivity. This corresponds to RJ45 connectors, where high-speed CAT7 and CAT8 connectors also require gold plating and additional shielding layers.

In CAT7 and CAT8 jacks, gold plating is added to the metal strips to enhance signal conductivity.

The RJ45 keystone jack has 8-pin contact points inside the front plug, corresponding to the eight wires of the twisted pair cable; on the back, there are four wiring columns on each side, with a polycarbonate housing and metal clips embedded in the wiring columns connecting to the contact points. Clear universal wiring color codes are marked on both sides of the keystone module, in two rows. Row A represents the T586A wiring mode, and Row B represents the T586B wiring mode. This is the most common RJ45 information module that requires a crimping tool.

RJ45 keystone jack has 8-pin contact points inside the front plug, corresponding to the eight wires of the twisted pair cable; on the back, there are four wiring columns on each side

The core of the RJ45 keystone jack is the modular plug. Gold-plated conductors or socket holes maintain a stable and reliable electrical connection with the modular plug contacts. The friction between the contacts and the socket further strengthens the electrical contact as the plug is inserted. The socket design incorporates an overall locking mechanism, ensuring maximum pull-out strength when a modular plug (such as an RJ45 plug) is inserted. The wiring blocks on the RJ45 jack connect the twisted pair through slots, and locking clips can secure the RJ45 jack in information outlet devices like .RJ45 faceplates.

The wiring blocks on the RJ45 jack connect the twisted pair through slots, and locking clips can secure the RJ45 jack in information outlet devices

Common unshielded RJ45 Jacks are 2cm high, 2cm wide, and 3cm thick, made by injection molding, with a housing that is resistant to high pressure, flame retardant, and UL rated 94V-0. They can be easily snapped into any M-series modular faceplate, bracket, or surface mount box, and can be installed at 90 degrees (vertical) or 45 degrees on standard faceplates. Special process design provides at least 750 repeated insertions, and the keystone module uses T568A and T568B wiring universal labels. It also comes with a white flat cable insertion cover. This type of keystone module typically requires a crimping tool. This unshielded keystone module is the most widely used in domestic integrated wiring systems, maintaining a consistent appearance from CAT3/RJ12, CAT5, CAT5E, to CAT6 jacks.

When we introduced the metal contact pins of the RJ45 connector, we mentioned phosphor bronze or bronze. However, many manufacturers' promotional materials claim that the metal pins in RJ45 connectors or keystone jacks are made of pure copper or oxygen-free copper. This is a misleading claim, often made to boost the product's perceived value. Both the pins in RJ45 connectors and the metal pins in RJ45 keystone jacks require high hardness requirements. However, 100% pure copper or oxygen-free copper pins are too soft and cannot pierce through the plastic insulation of the cable cores. Additionally, when wiring into the metal pins of a keystone jack, high hardness is necessary. Therefore, most RJ45 connector pins are made of bronze or phosphor bronze, but in RJ45 keystone jacks, phosphor bronze is predominantly used.

in RJ45 keystone jacks, phosphor bronze and gold plated pins are predominantly used

Phosphor bronze offers excellent machinability, corrosion resistance, and high hardness, wear resistance, and durability, making it widely used in mechanical, electrical, and aerospace applications. Bronze, on the other hand, has excellent electrical and thermal conductivity, along with high plasticity and toughness, making it commonly used in casting, electrical components, and metal parts. In keystone jacks, the front eight pins are made of bronze because they need only make contact, ensuring better conductivity. The metal pins in RJ45 connectors need less hardness compared to the metal pins in the wiring terminals of RJ45 keystone jacks. This is why phosphor bronze is widely used in the wiring terminals of keystone jacks.

phosphor bronze is widely used in the wiring terminals of keystone jacks because metal pins in the keystone jacks wiring terminals need more hardness

Phosphor bronze is an alloy containing zinc, copper, tin, and phosphorus, with phosphorus content typically reaching 5% or more. Bronze, in contrast, is a copper-based alloy typically composed of copper, tin, lead, zinc, and nickel. Phosphor bronze has a higher phosphorus content, while bronze has a broader range of components and more nuanced proportions. Phosphor bronze, which is an alloy of copper, tin, and phosphorus, is hard and is often used to make springs. It is used to deoxidize pure copper and bronze (Cu-Sn) with residual phosphorus and to improve mechanical properties such as toughness, elasticity, wear resistance, and corrosion resistance by adding 1% phosphorus. It is mainly used for wear-resistant parts and elastic components. Applications include computer connectors, mobile phone connectors, high-tech industry connectors, electronic and electrical springs, switches, slots, buttons, electrical connectors, lead frames, vibration plates, and terminals.

Phosphor bronze, which is an alloy of copper, tin, and phosphorus, is hard and is often used to make springs

Because of its high hardness, wear resistance, and corrosion resistance, phosphor bronze is frequently used in automated machinery, aircraft engine bearings, automobiles, railway vehicles, high-speed trains, and export agricultural product packaging. Bronze is commonly used in printing, far-infrared health products, fitness equipment, balcony railings, cosmetic accessories, audio equipment, and ancient architectural decorations. Phosphor bronze has a lighter color than ordinary bronze, appearing light red or pink, sometimes with a slight reddish tint, while ordinary bronze is more yellowish.

Phosphor bronze has a lighter color than ordinary bronze, appearing light red or pink, sometimes with a slight reddish tint

The core of the RJ45 keystone jack is the metal connection components, including the wiring terminal metal pins and the front eight pins. High-quality RJ45 keystone jacks feature gold-plated pins. The gold plating here serves the same purpose as in the RJ45 connector pins. The gold layer ensures a stable and reliable low-voltage signal connection between the wire or socket hole and the modular plug's spring pins. The electrical contact is further enhanced by the friction between the metal spring pins and the socket hole as the plug is inserted. The RJ45 keystone jack socket design incorporates a comprehensive locking mechanism, ensuring maximum pull-out strength at the interface between the plug and socket when an RJ45 plug is inserted.

The thickness of the gold layer in RJ45 connectors and keystone jacks can vary, ranging from 1 micron to 50 microns.

The thickness of the gold layer in RJ45 connectors and keystone jacks can vary, ranging from 1 micron to 50 microns. These gold layer thicknesses provide different performance and durability for various applications. The choice of gold layer thickness is based on its impact on the connector's wear resistance, conductivity, and lifespan. Gold plating significantly enhances the durability and conductivity of connectors, a common process in electronic components. While a thicker gold layer is preferable, a layer that is too thin can wear off easily during use, and thicker layers also come with higher costs, necessitating a balance between the two.

Gold plating significantly enhances the durability and conductivity of connectors While a thicker gold layer is preferable

A high-quality RJ45 keystone jack features a compact design, increasing the port density of the socket. The housing is made of ABS impact-resistant plastic material, with a dust cover to prevent dust and moisture ingress. High-quality keystone modules also use gold-plated spring pins to extend the keystone module's lifespan and improve transmission efficiency.

A high-quality RJ45 keystone jack features a compact design, increasing the port density of the socket

Most product descriptions for RJ45 keystone jacks highlight the use of ABS injection molding for the housing.

Injection molding involves injecting molten material, typically plastic or metal, into a mold under high pressure. The mold is precisely made to the desired shape and size.

Injection molding involves injecting molten material, typically plastic or metal, into a mold under high pressure. The mold is precisely made to the desired shape and size. The material is melted in a heated barrel and then forced into the mold cavity. The screw mechanism in the barrel facilitates this process, softening the material and ensuring even injection into the mold. Injection-molded products offer high precision, enabling the production of parts with extremely tight tolerances and consistent dimensions. This process allows manufacturers to create complex geometries and shapes with high accuracy, ensuring that each part meets precise specifications.

The structure of the injection machine ensure Injection-molded products offer high precision, enabling the production of parts with extremely tight tolerances and consistent dimensions.

Injection molding can produce parts with complex details and features, including thin walls, intricate patterns, undercuts, threads, and other challenging details that may be difficult or impossible to achieve with alternative manufacturing methods. Injection-molded parts are known for their durability and strength, ensuring even material distribution and excellent structural integrity, wear resistance, impact resistance, and environmental resistance. Although the initial tooling cost for injection molds can be high, it becomes highly cost-effective for large-scale production. Once the mold is made, the per-unit manufacturing cost significantly decreases, making injection molding an economical choice for producing identical or similar parts in bulk.

7.1 ABS Material

ABS, which stands for acrylonitrile butadiene styrene, is a versatile thermoplastic engineering plastic. It appears opaque and ivory-colored, with products that can be made in various colors and high gloss. ABS has a relative density of about 1.05 and a low water absorption rate. It exhibits good adhesion with other materials, making it easy to print, coat, or plate on its surface. With an oxygen index of 18%-20%, ABS is a flammable polymer that produces a yellow flame, black smoke, and a distinctive cinnamon smell when burning.

ABS plastic appears opaque and ivory-colored, with products that can be made in various colors and high gloss

ABS has excellent mechanical properties, with very good impact strength that allows use at extremely low temperatures. It has good wear resistance, dimensional stability, and oil resistance, suitable for bearings operating under medium loads and speeds. ABS exhibits better creep resistance than PSF and PC but worse than PA and POM. Its bending and compressive strengths are among the lowest for plastics. ABS performance is significantly affected by temperature. Its heat deflection temperature range is 93-118°C, which can be increased by about 10°C after annealing. ABS remains somewhat flexible at -40°C and is usable within a temperature range of -40°C to 100°C. ABS offers good electrical insulation that is unaffected by temperature, humidity, or frequency, making it suitable for most environments. ABS is unaffected by water, inorganic salts, alkalis, and many acids but dissolves in ketones, aldehydes, and chlorinated hydrocarbons. It is prone to stress cracking when attacked by glacial acetic acid (ice vinegar) or vegetable oils. ABS has poor weather resistance, with its impact strength reducing by half after six months of exposure to UV light outdoors.

As described above, using ABS for RJ45 keystone jacks would result in a lack of fire resistance. To overcome ABS's shortcomings, polycarbonate (PC) is often blended with ABS to create a PC/ABS alloy. This alloy combines the excellent properties of both materials, enhancing ABS's heat resistance and tensile strength while reducing PC's melt viscosity, internal stress, and improving processing, low-temperature impact resistance, and chemical resistance.

PC/ABS alloy combines the excellent properties of both materials, enhancing ABS's heat resistance and tensile strength while reducing PC's melt viscosity, internal stress, and improving processing, low-temperature impact resistance, and chemical resistance.

The primary drawback of PC/ABS is its weight and less-than-ideal thermal conductivity. The molding temperature for PC/ABS ranges between that of the two raw materials, 240-265°C, with temperatures too high causing ABS decomposition and too low resulting in poor PC flow.

PC/ABS composite materials approach the performance of low-smoke, Zeo-halogen (LSZH)materials, serving as a substitute with high temperature, fire, and impact resistance

PC/ABS composite materials approach the performance of low-smoke, Zeo-halogen (LSZH)materials, serving as a substitute with high temperature, fire, and impact resistance, increasingly used in various applications. Therefore, many high-quality RJ45 keystone jacks recommend PC/ABS as the housing material.

8. How To Judge the Quality of RJ45 Keystone Jacks

8.1 Judging the Quality of RJ45 Keystone Jacks by Appearance

According to the industry standard YD926.3, the term "information keystone module" is defined as "information outlet" and is categorized under "connecting hardware" in the cabling system. According to the standard ANSI/TIA-568, it falls under "Connecting hardware" as "RJ45 Jack." Depending on different standards and specifications, it may also be referred to as "computer keystone module," "keystone jack," etc. For simplicity, we commonly call it "RJ45 keystone jack." With the continuous development of network information, the demand for keystone jacks has increased. However, as the demand grows, the quality of products has become more uneven, with both high-quality and inferior products on the market. Since keystone jacks are industrial products, while there are methods to distinguish quality, it is often difficult for ordinary users or procurement personnel without professional instruments to truly judge the quality of keystone jacks. Today, we will share some methods to judge the quality of a module by examining its appearance, structure, and performance. Let's start with the overall appearance. Commonly used information modules include Cat 5e, Cat 6, and Cat 6A, which usually have mold marks, as shown in the figure below.

Commonly used information modules include Cat 5e, Cat 6, and Cat 6A, which usually have mold marks

RJ45 keystone jacks can be either unshielded or shielded. Unshielded keystone jacks: High-quality modules typically use polycarbonate material (engineering PC material), which performs better in durability in repeated use and the elasticity of installation clips. Some products use ordinary engineering ABS material, which is slightly inferior in quality. It is important to pay attention to modules made from recycled plastic, as they are poor in durability in repeated use and the clips are extremely prone to breaking, making them low-quality modules. When distinguishing, you can test the elasticity of the module's clips by hand. If the elasticity is poor and the clips are prone to breaking, it is a poor product. Also, check the appearance for fine workmanship. If the surface is not smooth, mold lines are obvious, edges are not rounded, and there are burrs, it indicates poor injection mold quality, production process, and material.

Shielded keystone jacks: The external structural components are usually made of two materials: tin-plated copper sheets or zinc alloy die-cast and then electroplated.

Shielded RJ45 keystone jacks: The external structural components are usually made of two materials: tin-plated copper sheets or zinc alloy die-cast and then electroplated.

In terms of full shielding performance, structural reliability, and service life, zinc alloy die-cast and electroplated shielded modules are superior to tin-plated copper shell shielded modules. Higher-grade shielded modules, like CAT6A, CAT7, and CAT8, no longer use tin-plated copper shielding because it can't provide full shielding. Currently, tin-plated copper shielded information modules still exist on the market. When encountering such products, one should carefully distinguish, as these modules are generally of lower quality. In addition to these two types, special attention should be paid to shielded modules with stainless steel as the shielding shell, as these modules are particularly low in quality. For shielded information modules with zinc alloy shells, attention should also be paid to the quality of the die-casting mold, production process, zinc alloy raw material, and electroplating process. Select products with high surface quality, smooth finishes, and even electroplating. Otherwise, the quality is likely to be subpar.

For zinc alloy shells keystone jacks, attention should also be paid to the quality of the die-casting mold, production process, zinc alloy raw material, and electroplating process. Select products with high surface quality, smooth finishes, and even electroplating

8.2 Judging the Quality of RJ45 Keystone Jacks by Product Structure

First, let's look at the 8-PIN gold pins inside the information module's socket, which are crucial for transmission performance. A. Visually inspect whether the gold pins are smooth and free of burrs. The surface of the gold pins on information modules is electroplated with nickel and then gold, with the metal contact area being gold-plated. Many high-end keystone modules are electroplated with 50u" gold. If the electroplating quality is poor, with insufficient nickel base thickness, inadequate gold plating, or even copper plating instead of gold, such gold pins cannot pass plug-pull tests and salt spray tests. The product surface will appear dull, with burrs, and may even develop a greenish surface, indicating poor product quality that will affect transmission performance. Observe the structure of the 8PIN gold pins. As networks have evolved, the design of gold pins has also seen continuous improvements. Especially with the increasing application of POE technology, the structure of gold pins has evolved from the previous fully parallel and straight structure to a three-layer S-shaped staggered structure.

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Fully parallel and straight structure: The friction point during insertion and the contact point after fixation are the same point, which affects POE performance. Additionally, the fully parallel and straight structure of gold pins does not separate or stagger, causing mutual interference during signal transmission and compromising link stability. Three-layer S-shaped staggered structure: The friction point during insertion and the contact point after fixation are not the same point, which meets POE performance requirements. Additionally, the three-layer S-shaped staggered structure effectively reduces interference between wire pairs during transmission, improving link stability. Secondly, examine the 8PIN wire-terminating conductor at the rear of the information module, which directly affects the cable termination quality of the module. High-quality modules typically use 45-degree angled terminal structures for crimping, whereas some lower-end modules continue to use 90-degree crimping terminals. As shown in the figure: 90-degree crimping: Poor durability in repeated use, and if the crimped cable is too thick, it may break the cable. If the cable is too thin, it may appear to be crimped but not pierce the core wire, leading to poor contact. 45-degree crimping: Good durability in repeated use, and regardless of the cable gauge, it ensures that the cable is not broken and guarantees conductivity.

8PIN wire-terminating conductor at the rear of the information module directly affects the cable termination quality of the module. High-quality modules typically use 45-degree angled terminal structures for crimping, whereas some lower-end modules continue to use 90-degree crimping terminals.

8.3 Judging the Quality of rJ45 Keystone Jacks by Transmission Performance

For such a professional industrial product as a keystone jacks, it needs to undergo numerous tests using very specialized equipment, which is usually not available to ordinary users and procurement personnel. Here's a method to assess the transmission performance of keystone jacks. We all know that before selecting a cabling system, there is a permanent link performance test. First, determine a qualified network cable and perform a 10-meter short link and a 90-meter standard link according to the permanent link model. Then use Fluke engineering test instruments to test. If the test results are all qualified, it indicates that the keystone jack is qualified. Moreover, a good module can compensate for the entire link.

Permanent link performance test:First, determine a qualified network cable and perform a 10-meter short link and a 90-meter standard link according to the permanent link model. Then use Fluke engineering test instruments to test. If the test results are all qualified, it indicates that the keystone jack is qualified.