INFODEV     ISO 9001:2008

Intelligent Spread Spectrum Modem


Once the vehicle has returned to the garage, passenger-counting data needs to be transferred from the on-board microcomputer to a PC computer for analysis.

A high-speed spread-spectrum transceiver installed inside the bus transfers its data to the PC computer in the garage. The spread-spectrum modem's long range provides more flexibility, allowing data transfers at distances of up to 500 ft. between the on-board and garage units. Hence, data transfer doesn't have to be done during refuelling.

It takes 20 to 30 seconds to transfer a full day of logging. A unit with a full memory of logging information will take about 3-4 minutes to transfer.


  • Error-free data exchanges are ensured by an auto-correcting protocol.
  • The PC produces diagnostic messages reporting the proper operation of communications.
  • A transmitter signal strength measurement can be used to diagnose device malfunctions.
  • Infodev's RF-Link incorporates a wide range of high-performance radio transceivers which meet the stringent demands of military, domestic and international regulatory agencies.
  • Status lights simplify system diagnostic.
  • The system's wide range offers increased flexibility.
  • The ISSM-20’s rugged design withstands harsh environmental conditions common to public transit vehicles.


Installed on-board the vehicles and in the garage, the units transfer passenger-counting data to the garage computer and upload the onboard computer's software when necessary. The intelligent spread-spectrum modem can also be used in a traffic light priority system.

Frequency band: 2,402 - 2,478 Ghz
Radio type: Frequency Hopping Spread Spectrum (FHSS)
Indoors range: Up to 150 m / 500 ft.
Outdoors range: Up to 3048 m / 10 000 ft..

Networkable TTL-RS-232, Rs-422, RS-485, J1708
Speed: Up to 115 200 bps:

8 to 32 VDC
Consumption in communication: 1,8 W, 150 mA @ 12 VDC
Consumption when idle: 0,84 W, 70 mA @ 12 VDC

Storage temperature: -40 to 60oC / -40 to 140oF
Operation temperature: 0 to 60oC / 32 to 140oF
Humidity: 10-95% not condensing internally

Type: Diecast aluminium
Weight: 250 g / 8,8 oz
Size: 11,2 x 6,1 x 3 cm / 4,4 x 2,4 x 1,2 in.
Colour: Black

ISSM-20 : Spread-spectrum radio modem.


The spread-spectrum modem can be installed in all vehicle types:

See how data is transferred between the vehicle and the garage