What does RJ mean?
No other connector has such a track record like the RJ45 which long since became the dominant connector in copper data networks.
“RJ” is the acronym for “registered jack” and the number that follows denotes the exact type. Interestingly enough, no “RJ45” can be found in the relevant standards, nor “RJ-45” for that matter. Cabling standards recognize a modular 8P8C connector, where “8P” means the connector has eight positions for electrical contacts and “8C” means eight contacts are present. International cabling standards also point to connectors specified in the IEC 60603-7 series of standards. Regardless of these proper designations, the short term “RJ45” is preferred in daily life.
RJ45 cabling categories and standards
The international standard series IEC 60603-7 and the European standard EN 60603-7 which is based on it specify different categories of shielded and unshielded RJ45 connectors, categories 5, 6, 6A and 8.1. being the most important ones.
The standards for “RJ45” connectors:
The standards for “RJ45” connectors:
General, up to 3 MHz: IEC 60603-7, European standard EN 60603-7
Category 5, unshielded: IEC 60603-7-2, European standard EN 60603-7-2
Category 5, shielded: IEC 60603-7-3, European standard EN 60603-7-3
Category 6, unshielded: IEC 60603-7-4, European standard EN 60603-7-4
Category 6, shielded: IEC 60603-7-5, European standard EN 60603-7-5
Category 6A, unshielded: IEC 60603-7-41, European standard EN 60603-7-41
Category 6A, shielded: IEC 60603-7-51, European standard EN 60603-7-51
Category 8.1, shielded: IEC 60603-7-81, European standard EN 60603-7-81
RJ45 connector technology
Terminating cables with RJ45 plugs and jacks
The American cabling standard ANSI/TIA-568 specifies two pin/pair assignments to connect a four-pair cable to RJ45 plugs and jacks: T568A und T568B. T568A was originally used for military applications and is still mandatory for US authorities and the military.
Pin/pair assignments T568A and T568B correspond to the assignments “option A” and “option B” respectively of EN 50174. Both options are equal as far as data transmission is concerned, however both ends of the cable must be terminated the same way. In a link, segments of either pin/pair assignment can be mixed as long as a segment is terminated the same way on both ends. To give an example: The horizontal cable can be terminated in the patch panel and in the outlet using assignment T568B and the patch cords can be terminated using assignment T568A.
RJ45 outlets with connecting blocks and with RJ45 modules
Traditional Outlets and patch panels used to have connecting blocks which were soldered to printed circuit boards (PCBs). The constantly rising demands on the cabling and the growing time pressure during installation could be answered successfully with RJ45 modules, which means every cable end is terminated with an RJ45 module of its own. The modules are just clicked into the empty patch panel or outlet. Links with individual modules typically have a higher transmission performance than traditional connecting hardware with connecting blocks and can be terminated much quicker. Also links can be added later much easier and more cost-effective.
Power over Ethernet (PoE)
RJ45 connectors not only transmit ever higher data rates, they also have to transmit ever higher electrical currents to remotely power devices with Power over Ethernet. This is a very economical and convenient solution as it omits the need for electrical power supplies, sockets and cabling. Nowadays up to nearly one ampere runs through a pair or wires, which is much more than the RJ45 was originally designed for and which might lead to severe damaging of the plugs‘ and jacks‘ contacts. When plug and jack are unmated under load, sparks occur which irreparably damage the contacts and so the connectors cannot transmit data anymore. This can be avoided by using contacts which are designed to meet the requirements of the different Power over Ethernet versions. The area where the contacts are damaged (red) is far away from the area where the data is transmitted (green). Even after repeated unmating under load this Telegärtner RJ45 jack will deliver maximum performance (however, unmating under load is not recommended as standard operation, of course).
RJ45 connectors from Telegärtner
RJ45 jacks and modules
The portfolio of RJ45 jacks and RJ45 modules from Telegärtner comprises three different products: The AMJ Module K, the proven standard module for simple installation situations, which convinced with its high user-friendliness as well as its very high mechanical robustness and has already been installed millions of times. The AMJ-S module is our slim RJ45 jack for confined spaces with integrated cable shield contacting, integrated strain relief and with a metallic snap-in latch for low-impedance potential equalisation. And the third RJ45 jack is our newest and shortest module in the series with an extremely high system reserve.
The shortest RJ45 module
Flat cable raceways, floor boxes and flush-mount installations offer only little space. Standard RJ45 modules very often protrude the module carrier and do not leave enough space for proper cable routing. This results in kinked cables and in links that fail when being tested. Outlets with connecting blocks on the front as well as particularly short RJ45 modules leave enough space for maintaining the minimum cable bend radius even under adverse conditions and in tight spaces. Short RJ45 modules like Telegärtner’s AMJ-SL leave enough space to maintain the proper cable band radius.
RJ45 Patch cord
Patch cords are often neglected – with fatal results, because even the most powerful infrastructure stays behind its possibilities when low-quality patch cords degrade the transmission channel‘s performance. But how can one tell whether a patch cord is high or low quality? Once again Telegärtner was leading the way: The Telegärtner test lab provided the world‘s first test adapter for Category 6A RJ45 patch cords. The test set is even more demanding and more precise than specified by the international standards.
Easy assembly with the field-installable RJ45 connector
The field-installable RJ45 plugs of Telegärtner’s MFP8 series can quickly and easily be installed on the horizontal cable. This comes in handy when outlets are not desired for esthetic or security reasons, e.g. to connect WiFi access points or IP cameras to the network. In an MPTL, the horizontal cable is terminated with an RJ45 plug, so no outlet is needed. This is also common in industrial plants and even home office cabling omits outlets and patch cords. High-quality plugs can be installed on site quickly and easily and can be used for any kind of IT application from the plain old telephone system to leading edge technologies like 40 Gigabit Ethernet.
LAN connection for mobile IT equipment
The DDCP link offers users and network managers an easy way to protect expensive mobile IT equipment with an RJ45 port from being damaged. Should the mobile device move further than the connected patch cord allows, the DDCP link releases the cord and by this makes sure that the RJ45 port or contacts are not damaged. This prevents from costly repairs. The withdrawal force is below the value specified for plugs and jacks by IEC 60603-7 which makes sure the connection of RJ45 cord and DDCP link is unmated first. However, the retention force of the connection is high enough to prevent from unwanted unmating at low forces. The DDCP link can be integrated into existing links easily, e.g. by inserting it between outlet and cord or between cord and electronic device.
Our unshielded modules
Shielded or unshielded? The answer to this question depends on the project at hand. Depending on grounding/ bonding, low-frequency magnetic field, available space and budget, unshielded cables can be an extremely interesting and cost-effective alternative. Telegärtner's product portfolio includes unshielded RJ45 connectors and modules.