From Xmultiple's Engineering Department.

Xmultiple does recommend EMI fingers for reduction of EMI for most product designs.

RJ connectors EMI tabs provide the connector gound to the enclose or chassis. A typical line interface configuration that is used in Ethernet and other networking equipment is where the PCB layout has separate ground planes that are specifically partitioned to keep different types of signals localized in distinct functional blocks. With this typical line interface configuration, there are several important factors which prevent EMI from being coupled onto the data transmission cables. One factor is that the RJ connector is placed on a ground plane that is electrically separated from the rest of the PCB and connected to the system chassis. EMI tabs are used on the shielding ot provide this ground. This effectively creates a barrier that isolates the RJ connector from the noisy digital signal currents present on the PCB. The EMI tabs on the RJ connectors shielding touch the enclosure or chassis and the resulting ground plane shields the RJ connector from the electromagnetic fields present on the PCB and inside the system enclosure.

Please call us so we can discuss your specific design regarding this requirement.)