8 years ago
#13 Quote
OmniSense sensors use the FCC approved 902-928 MHz ISM frequency band.  Operation in this band is subject to FCC approval.  Obtaining FCC approval requires independent third part lab tetsing verifying the equipment meets the FCC 15.247 standard for operation in the ISM frequency band.  If the FCC accepts the test results a FCC Grant is issued authorizing the products to operate.  The FCC grant that OmniSense equipment operates under can be found here https://apps.fcc.gov/oetcf/tcb/reports/Tcb731GrantForm.cfm?mode=COPY&RequestTimeout=500&tcb_code=&application_id=522466&fcc_id=RY20002.

All that said, does FCC certification mean the equipment will not cause interference?  The short answer is yes.  The longer answer is that the 902-928 MHZ ISM band is designed for short range low power (less than 10 mW transmit power) devices that use frequency hopping spread spectrum modulation techniques. Put more simply, think of it as a 64 lane freeway with cars randomly changing lanes every 0.4 seconds or faster and following a rule to check before making a lane change and if the lane is in use, select another lane.  To start running into interference problems you would have to have hundreds of devices transmitting at the same time within a few hundred feet of each other.  A typical omnisense sensor wakes up once every few miniutes, transmits a message in 0.25 seconds or less, and then goes back to sleep.  

Finally, the proof is in the pudding. OmniSense monitoring systems are in large scale (greater than 400 sensors and 20 gateways at some job sites) use in multiple health care facilities in the US with no reported problems of interference.