Announcing 2.4 GHz FH radio units for remote control and monitoring

Circuit Design, Inc., the leading supplier of low power radio modules, is releasing the High/Low level status transmitter unit KST2.4S and the receiver unit KSR2.4 for industrial applications.
KST2.4S/KSR2.4 has an embedded radio module NK-2.4Y that has obtained US FCC certification and Japan radio type approval. There is no need to apply for any additional radio certification.

The unit contains the radio module, output photo-MOSFET, and communication monitor LEDs. This makes it easy to design radio systems for the start/stop of drive equipment and monitoring High/Low level changes.

The radio unit operates with our own proprietary frequency hopping method. This enables simultaneous control over multiple systems in the same area without radio channel management. It also offers a Hamming distance of 6 which guarantees reliable communication. The LINK LED in the communications monitor indicates the link status of the radio at all times.

The dedicated harness provides an interface for the power supply, 6 inputs or 6 outputs, and the wireless link monitor output terminal. The receiver unit KSR2.4 can control loads of up to 35V DC 200mA with the photo-MOSFET output. High level or Low level input/output settings are both possible*.
*Please refer to the connection examples

Available from December 2021
Product details page

Technical features

  • FCC Part 15 / ARIB STD-T66 Compliant RF module (NK-2.4Y) included
  • 2.4 GHz Frequency Hopping two-way communication (1:1 communication only)
  • 6 inputs (KST2.4S) / 6 outputs (KSR2.4)
  • Reliable radio communication - Hamming distance 6, CRC-16 Error detection
  • Line of sight communication range 100 m
  • 3 selectable output modes (One-shot, Toggle, Momentary)
  • Operating voltage 6 – 24 V, 30 mA max. (KST2.4S), 80 mA max. (KSR2.4)**
    ** All photo-MOS relays are on, no load conditions
  • Operating temperature range -20 - +60°C
  • Size 55 x 45 x 12.5 mm (both KST2.4S and KSR2.4, excluding protrusions)


  • Open/Close control for gates and shutters
  • Monitor and alarm system with threshold level control for sensors
  • Start/Stop control for various driving / motor equipment


Connection examples


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About Circuit Design

Circuit Design, Inc. designs and supplies low power radio modules for various application fields such as telecontrol, telemetry, alarms, serial data transmission and audio. The products comply with European ETSI, US FCC, Canada ISED and Japanese ARIB standard.

Quality is assured with an ISO9001-certified design and manufacturing process based in Japan.

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IEN Europe