Which filtered interface for which signal?

JRE offers two USB 2.0 filtered interfaces, single and dual channel. The single-channel JRE USB 2-1 rejects frequencies above 880 MHz while passing data and power between a host computer on one side and a USB device on the other. Standard USB Type A connectors appear on each side of the adapter.

It's fully USB compliant, so the correct enumeration process runs and any test 'hiccups' are properly exchanged between devices — there are no undetected hang-ups, which is a real problem when using fiber optic or other such interfaces. Inside, the data lines are a balanced bi-directional pair and power is a balanced power-and-return pair. The data-line filters pass the full 480 Mbps of USB 1 or 2 data while rejecting greater than 80 dB from 1 GHz through 6 GHz; the power-line filters pass DC power and return while rejecting greater than 80 dB from 1 MHz through 6 GHz. The dual-channel version adds a second set of USB 2.0 ports, each terminated in a USB cable at least 4 inches long with standard USB 2.0 pinout.

See the JRE USB 2-1 single-channel and JRE USB 2-2 dual-channel filtered interfaces.

Because at SuperSpeed rates the data lives in the same frequency range as the RF you're trying to shield out. Earlier filter designs used low-pass filtering on the data lines to attenuate interfering wireless RF — but as data speeds rose, the data signals moved up into that same band. A simple low-pass filter would attenuate both the data and the interference, so it can no longer be used.

JRE's USB 3.0 SuperSpeed filter works on an entirely different principle. The patented design applies signal-phasing techniques and topology to filter out all RF except the desired data signals. That ability to discriminate data from undesired RF matters most when testing at USB SuperSpeed rates — where the signaling rate falls within wireless frequencies — or when the potential interfering frequencies fall inside the pass band of a low-pass-filtered USB interface, as with wireless key fobs or RFID devices. JRE offers the interface in single and dual channel. (For more on the underlying approach, see Patents & Innovation.)

See the JRE USB 3-1 single-channel and JRE USB 3-2 dual-channel SuperSpeed filtered interfaces.

The JRE LAN-1 is a 10/100/1000 Ethernet-compliant low-pass filter in a machined aluminum housing that shields all 8 signal lines, so it works with standard Ethernet and any other format using an RJ-45 connector. It's designed to reject frequencies above the 700 MHz cellular band while passing data between RJ-45 devices — routers, switches, access points, and other Ethernet gear.

See the JRE LAN-1 RJ-45 filtered interface.

Fiber optic I/O offers the ultimate in RF shielding: there's no ohmic connection, only light. JRE's pass-through connectors let you feed fiber cables — connectors already attached — straight through the plate, so there's nothing to terminate in the lab or field.

For operation up to 6 GHz, the JRE FPT passes up to 5 fiber cables through a removable machined plate; the slotted opening adjusts to grip the cables securely and control the portal size when fewer cables are used. For microwave frequencies up to 28 GHz, use the Fiberplex WGF-6 pass-through: remove the Allen screw and center metal insert, pass the cable and connector through the center (up to six cables), then replace the insert and tighten. Its precise machining holds excellent isolation deep into the microwave region — over 60 dB at 25 GHz and well over 100 dB below 10 GHz.

See the JRE FPT (to 6 GHz) and the Fiberplex WGF-6 (to 28 GHz).

For general serial I/O, JRE filtered DB connectors can be used alone or with adapters to match almost any connector style. JRE stocks a range of capacitance values that trade data rate against isolation: 1000 pF for data up to 10 Mbps, 100 pF up to 100 Mbps. Higher capacitance gives higher shielding effectiveness but slows the data; lower capacitance allows faster data but poorer RF isolation — tell us the signal and we'll match the value to it.

One important limit: don't use these adapters and filtered DB connectors for high-speed USB, Ethernet, or HDMI signals. Doing that well requires an extensive understanding of the capacitive loading on those data lines — for anything beyond low-speed serial, use a purpose-built JRE filtered interface instead.

See the filtered DB9, DB15, and DB25 connectors.

For filtered power entry, JRE offers 4-terminal and 6-terminal barrier strips with 2500 pF feedthrough filtering, rated 100 VDC / 250 VAC at 20 A — heavy-duty enough for RF-filtered AC or DC power into the enclosure. For convenience inside the chamber, AC mains power strips are available in 4, 5, and 6 outlet USA configurations, plus 4- and 6-outlet European Schuko and a 5-outlet universal option.