What’s new in infrastructure CAT-5 and CAT-8 balanced pair connectors?

CAT-5e or Category 5 enhanced, a second generation CAT-5 infrastructure interconnect using non-shielded RJ-45 jack and plug connectors, has been a dominant 1 GbE port high volume market for several years. However its usage for LAN is past its peak as many more 10 GbE ports requiring CAT-6a or CAT-7a connectors are being shipped and represent the largest volume RJ45 usage.

RJ45 connectors are also no longer found on consumer desktop and mobile electronic devices as they take up to much room and have been replaced by smaller USB connectors and interfaces. But CAT-5e usage for IoT, sensor networks and industrial automation applications still provide a healthy market segment. CAT-5e, 100-MHz interconnect has been around for a long time and there is a huge variety of product types relative to mountings, locking or latch fasteners and many other features. Most products have a very utilitarian design and look. Material cost and product price are extremely minimal. Crimp and IDC wire termination options are available for both jack and plugs.

CAT-6a or Category 6 augmented, a 2nd generation CAT-6 infrastructure interconnect, uses RJ45 connectors that have significantly improved electrical signal integrity features that meet the 500 MHz requirements of TIA and IEC/ISO specifications. Newer 10GBaseT applications have driven the usage of shielded RJ45 connectors and cables by reducing crosstalk. Current telecom rooms and enterprise datacenters have required new features like LED light tubes that are useful as system function and management indicators. Feature improvements include better material usage to handle the power wattage required to support the different power-over-Ethernet specifications. Some product types have improved industrial designs that satisfies the need for the “jewelry look” in professional AV applications.

CAT-7a, a 2nd generation CAT-7 infrastructure interconnect, uses the newer modified shielded RJ45 connector system from Nexans. It is called GG45 and is in the IEC60603-7-1 specification. Historically RJ45 plug connectors used crimp or IDC terminations with the wire-form or stamped contacts, but even more stringent electrical requirements have resulted in the use of a plug PCB connector. Both OCC and The Siemon Co. offer premier RJ45 products with their patented PCB plug connectors for very fast field installed cabling, but there has been a trend to use factory-terminated cable assemblies to save installation time and cost. CAT-7a usage is much more common in Europe and Asia versus North America. Overall volume is still smaller than CAT-6a usage globally. The GG45 connector is not backward compatible with older RJ45 connectors as the contact pairs have been relocated to improve electrical transmission and crosstalk isolation.

There has been some interesting but moderate market share use of cross-architecture interconnect applications. You can buy adaptor modules for 10BaseT Ethernet that have a CAT-7a Jack connector on one end and a SFP plug connector back-to-back on the other end of a single PCB within a shielded housing.

CAT-8.1 standard and applications call for the GG45 Nexans augmented RJ45 that works well at 1.6GHz and supports the newly developing IEEE-802.3 spec for 25BaseT links. It fits best within certain datacenter connectivity usage and cost restraints. The Siemon Co.’s Tera connector is also used for some CAT-8.1 applications and has been standardized in the IEC61076-3-104 spec.

CAT-8.2 2GHz standard and applications require using Siemon’s Tera receptacle and plug, a non-RJ type that is more RF friendly, with lower insertion loss. However the TERA is a slightly larger size form factor connector compared to RJ45 connectors although panel space is always critical. But it can support more than one application versus the GG45 connector with its very isolated shielded contact pairs for the large and growing “smart building” market segment. More limited market segments and applications may cause a smaller, lower volume ramp up versus older CAT-5e LAN connector roll out.

There have been some customized cable assembly applications that had CAT-7a or CAT-8 balanced, shielded twisted pair raw cable wires, soldered terminated directly to the pad field of a paddleboard PCB SFP+ plug connector on one or both ends; thus plugging into a SFP+ cage and edge connector port. These were designed, tested and shipped successfully for several application specific programs. It seems that one could also terminate CAT-8.1 or CAT-8.2 cable wires and pair shields to a new smaller microSFP paddleboard PCB plug and outer shield to its metal housing and then plug into a new microSFP port connector.

Another adaptor assembly type possibly being developed is a one-piece module consisting of a CAT-7a or CAT-8.1/8.2 Jack connector back-to-back to a microSFP plug for 25BaseT or 40GBaseT adaptor assembly.
CAT-8 connector usage will likely be much more moderate because of the 30-m length maximum length and large cable AWG and bundle diameters. Longer reach applications tend to use many more wireless and optical interconnects solutions. So CAT-8 will be used mostly as a patch cord infrastructure option for emerging 40GBaseT applications and many some ToR to Leaf Server applications.