Electromagnetic signals can be modified in terms of wavelength and amplitude, which are crucial for the functionality of devices like garage door openers. Each wireless device typically operates at a specific frequency, often with slight variations to avoid interference. While multiple devices can share the same frequency, they use unique modulation techniques to transmit distinct codes, ensuring that only the intended device responds. Modern systems often employ digital modulation for efficient spectrum use, allowing multiple controllers to operate on the same frequency without conflict. This approach minimizes the risk of accidental activation by neighboring devices.