The frequency bands that 802.11b and 802.11g operate in are 2.4GHz bands, which allow for longer range but lower speed than higher frequency bands such as 5GHz or 6GHz bands used by newer standards such as 802.11a/n/ac/ax.

NFC stands for near-field communication, which is a wireless technology that allows two devices to exchange data when they are in close proximity (usually within a few centimeters). NFC is commonly used by mobile devices to process payments at kiosks, such as Apple Pay or Google Pay. Wi-Fi 6 is a wireless standard that provides faster speed and lower latency than previous versions of Wi-Fi. Bluetooth is a wireless technology that allows devices to communicate over short distances (usually within 10 meters). RFID stands for radio-frequency identification, which is a wireless technology that uses radio waves to identify and track objects that have RFID tags attached to them

The most common reasons you may be seeing the "No Signal" message: The projector and the source device are not connected correctly.
The first action should be to check the video cable and replace it if necessary, as the error message suggests that the projector is not receiving a signal from the laptop. Verifying that the projector is turned on and checking the bulb would come after verifying the video cable.

802.11ax, also known as Wi-Fi 6, has the longest range and the highest wireless throughput of all the wireless technologies listed. Reference: CompTIA A+ Certification Exam Guide, 220-1001, Chapter 3

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