PIR frequency fransmitter question Wireless Alarms

[mister accavanno <mraccavanno357@xxxxxxxxx>]

I understand that most units transmitting to the Main Control Unit are
operating on the 315mhz, 433mhz, and the 868mhz frequencies. Is there
a reference to find out which companies, or which particular sensor
units are using a particular frequency? I know that certain car
remotes interfere with certain sensor devices. Can I have some
elaboration from some of the more Knowlegeable professionals on which
companies use which frequencies.