You can use this third-party tool: https://tokbox.com/developer/tools/precall/results. This will conduct a pre-call test to check whether the camera and the microphone are accessible. Based on the results, it will provide recommendations. This also checks the browser compatibility. The screenshots below show the possible results/recommendations displayed after the test.
Scenario 1: Camera and Microphone accessible. The browser is compatible.
Scenario 2: Camera and Microphone not accessible - Click on Continue and Allow on the next prompts
Scenario 3: Incompatible Browser
Please note, that once the test is conducted, the test needs to be closed before trying to join a VSR session.