DSSS Low Power Radio TransceiverSTD-502-R

The STD-502-R 2.4 GHz transceiver uses direct sequence spread spectrum (DSSS) modulation and a true diversity circuit, enabling reliable communications even in the congested 2.4 GHz band.
The STD-502-R complies with the European ETSI EN300440, U.S. FCC Part 15.247, Canadian ISED RSS-210 standards and Japanese ARIB STD-T66, making it ready for the global market.

Low power consumption and battery operation give the STD-502-R the performance demanded for applications where long range and reliability are required.
The transceiver uses a transparent data interface to enable users to communicate using their own protocols.

The modules can be set easily via the UART interface using dedicated commands.
Circuit Design developed an onboard ASIC containing SS correlator (a key part of spread spectrum communications) instead of relying upon conventional RFICs. This ensures long term supply for industrial applications.



  • CE, FCC, ISED and ARIB conformity certification
  • Uses direct sequence spread spectrum (DSSS) modulation
  • A true diversity receiver containing two built-in receiver circuits
  • Module settings using dedicated commands
  • Data communication using transparent interface
  • Low power operation
  • 77 channels
  • Communication LOS: 300 m


  • Industrial telecontrol
  • Telemetry Systems

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Parameter Specification Remarks
Applicable standard EN 300 440
FCC part 15.247
Communication method Simplex
Transmission method Direct sequence spread spectrum
Emission type F1D FSK
Frequency 2402.5 to 2478.5 MHz
Number of RF channels 77
Channel spacing 1 MHz
Data bit rate 9.6 k / 19.2 kbps
Chip rate 144 k / 288 kcps
RF connectors RP-SMA x 2 Nominal 50 ohm
Spreading code 15 Chips M-sequence
( 111101010001100 )
temperature range
-20 to +65 degree C No dew condensation
Supply voltage 3.3 to 5.5 V DC
Supply current TX: 55 mA typ.
RX: 65 mA typ.
Dimension 50 x 30 x 9 mm Not including connectors
Weight 24g

Transmitter Part

Parameter Specification Remarks
RF output power < 10 mW e.i.r.p.
TX data input Digital L = 0 to 0.25
H = Vref - 0.4 to Vref

Receiver Part

Parameter Specification Remarks
RF Input level < -13 dBm
Receiver sensitivity -93 dBm 19.2 kbps, BER 0.1%
RX data output Digital L = GND, H = Vref


Parameter Specification Remarks
RF Data Interface
Port DO / DI / CLK
Data bit rate 9.6 k / 19.2 kbps Sync: CLK terminal
Command interface
Port TXD / RXD
Interface UART communication (RS232C format)
Communication method Asynchronous
UART bit rate 19.2 k / 38.4 k / 57.6 kbps
Flow control None
Other parameters Data length: 8 bits / Parity (None) / Stop bits 2

External View



Data Sheet

Version 1.6 PDF

Operation Guide

Version 2.2 PDF


Operation Guide

Version 1.0

Evaluation Tools: TB-STD502

The TB-STD502 evaluation board allows you to evaluate our STD-502 module and perform range, data packet and switching signal transmission tests. Onboard LEDs, CH switch, ID switch and push buttons allow you to easily make switching signal tests and packet tests with packet error indication.

The boards do not include both modules STD-502. Please order them separately if needed.


  • 4-push buttons and output LEDs.
  • Channel and ID switches
  • External input/output pins
  • Receiving antenna LED indicatorPacket test function
  • Transmission mode DIP switch setting

External View

Board x 1
Spacer x 4