Finding details on a wireless device with an IC ID is fairly simple. First, you will need to locate the label on the product. IC IDs may be printed on the label in the battery compartment and perhaps under the battery, many models list just “IC” rather than “IC ID”.
Once you have the IC ID, using the following form or at this IC Search Page
The device details page will include information such as “Approved Operating Frequencies” in MHz
Can’t find IC ID: 649E-SMT390