Low Voltage MIL-STD-188-125-1A
HEMP-Rated Filters

TSS USA Manufacturing’s LV line of low voltage HEMP filters are tested and certified to meet the production requirements of MIL-STD-188-125-1A and MIL-STD-188-125-2.

Filters are a standard aspect of addressing electromagnetic radiation (EMR) to provide optimum performance of circuitry and equipment.

For mission-critical applications, though—perhaps important military equipment monitoring the safety of the country or maybe a commercial installation providing power, a water processing plant, cloud computing for companies, telecommunications, food, transportation, energy, or other important services—this is not enough because of potential interruption by electromagnetic pulses (EMP) and high-altitude electromagnetic pulses (HEMP).

EMPs are intense transitory bursts of EMR that can interfere with communications, power, and other aspects of electronics equipment and services and even destroy equipment at a distance. These energy surges can come from natural sources such as lightning or solar flares, or from various technological systems. In the latter case, an EMP may be intentional—i.e., it may come from a device specifically designed to create intentional EMI, Electromagnetic interference, (IEMI)—or it may result from problems with nearby electrical and electronic systems.

Then there is HEMP, the result of a directed energy weapon (high probability) or nuclear device (low probability) detonated high in the atmosphere. This is done with the intent to destroy equipment, take out entire power systems, disrupt communications, and otherwise cause havoc.

An EMP, whatever the source, can enter a facility and equipment through incoming cables or wires, especially from power sources. The high resulting transients, whether a power surge or higher frequency signal, can devastate equipment not designed to operate with such outside interference. They can be particularly harsh on standard communications and infrastructure installations, such as analog and data lines for telephone, HVAC controls, and fire alarms.

To protect against that eventuality, organizations can incorporate the use of HEMP-rated filters that can suppress the transient signals and protect equipment from the effect of EMP or HEMP.

TSS USA Manufacturing offers a range of 2-line, 3-line, and 4-line HEMP standard filters suitable for single- and three-phase main supplies. The HEMP standard filters are appropriate for use on both fixed and mobile shielded rooms as well as general installations. While primarily intended for the military, they are also applicable to mission-critical public and private infrastructure operations and facilities.

All TSS USA Manufacturing HEMP standard filters are designed for use on 300Ω/600Ω analog and data lines for telephone, thermostats, and fire alarms. With high- or extended-performance, they are available with transient suppression.


  • Performance exceeds 100dB and extends beyond 40GHz
  • Choice of packaging and mounting styles
  • Filter circuits meet the requirements of UL1283
  • Circuits supplied as high symmetry matched pairs
  • Pass band ripple <2dB (300Ω)
  • Filters incorporate self-healing capacitors for high reliability
  • Temperature range -40°C to +60°C
  • RoHS compliant

Custom designs available.

TSS USA Manufacturing operations are in the U.S.A. and source raw materials and components predominately from the U.S. to serve your critical operations. TSS filters meet the FAR 52.225-1 Made in America.

Prepare for any potential HEMP event and secure your filters to protect your critical infrastructure with our extensive engineering services—available for no extra cost.