Feature: Connectors
• Manufactured cost: The price points for plugs and jacks are very cost-effective when compared to other I/O connectors. The popularity of the connector over time has also lowered its cost.
• Ease of termination: The RJ45 is quick and easy to terminate, with all eight contacts being terminated in one move.
• Latching mechanism: The latching mechanism that secures the connection is invaluable in networking applications, where outages are both costly and time-consuming to troubleshoot. The design of the latch is such that there is a positive click when the plug is fully inserted, and just-right pressure must be exerted to un-latch the plug.
• Protection: When the plug and jack are mated, the contacts are located well inside the jack housing, reducing the risk of dust ingress.
• Durability: The location of the contacts in the jack makes it robust. RJ45 connectors include strain reliefs and are often over-moulded to provide additional support.
Ethernet technology advances The first Ethernet standard supported by copper cabling and utilising the RJ45 connector was 10Base-T, with maximum data transmission speeds of 10Mbps. The latest Ethernet standard for copper cabling is 10 Gigabit Ethernet – also known as 10G Base-T – and this supports data transmission speeds to 10,000Mbps. Hence, the inevitable question is: How can a thirty-year-old connector system still be suitable? The majority of developments to enable these higher data
transmission speeds have been non-connector. The twisted pair cable used with RJ45 plugs has been enhanced dramatically to improve crosstalk and attenuation parameters required by the latest Ethernet standard. The original cable used for 10Base-T cabling was for Category 3 speeds; we are now looking at Category 6A cable to achieve 10GBase-T speeds, with Categories 4, 5 and 6 cable in between. The combination of materials used in the cable construction, the added shielding, the lay of the twisted pairs and use of “separators” have all contributed to this improved performance. In addition to cable improvements, the signal encoding
protocols used to transmit data have also been modified to achieve the latest speed requirements. This impacts how the electronic devices, such as switches and routers, process signals. That’s not to say that the RJ45 interface remains unchanged,
as there have been minor modifications to RJ45 plugs, too. The fundamental design of the plug has not changed but cable “guides” or inserts have been added to ensure the required amount of twist is retained prior to termination. This is critical to achieve highest performance levels. So, it is clear there have been multiple factors at play to
enable a thousand-fold increase in data transmission speeds. The ingenuity of the original RJ45 connector design made it extremely popular and practical, and influenced the decision to continue using it for copper Ethernet networks. This in turn led to a review of the complementary technologies in the system to extend its working life.
RJ45 product developments Over its thirty-year life, we have seen an expansion of this connector’s options, primarily in the networking industry where costs must be controlled. Examples of new product designs and functionalities
include: • Multiport jack assemblies – used in patch panels and networking devices, and in increasing connector density in 19” rack/equipment applications, as well as to save time in production.
• Jacks with integral LEDs – these assist with system diagnostics and troubleshooting and can also be linked to real-time software.
• Jacks with magnetics – used to support PoE networking applications, which has extended the use of this connector even further. Te RJ45’s flexibility and original well-thought-out design
have enabled it to stand the test of time very successfully. Today it is used with technology well beyond its original design remit and, yet, the design looks set to continue for years to come.
www.electronicsworld.co.uk December/January 2023 45
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