How is over-the-air access to IRLP nodes accomplished?

Over-the-air access to IRLP (Internet Radio Linking Project) nodes is accomplished using DTMF (Dual-Tone Multi-Frequency) signals. DTMF signals are the tones generated when pressing the keys on a telephone keypad, and they are used in radio communication to send commands or information. In the context of IRLP, when a user wants to connect to or control an IRLP node, they can do so by sending specific DTMF tones over the air.

This method provides a reliable way to interact with the node without needing a direct internet connection, making it feasible for amateur radio operators to engage in long-distance communications or link with other nodes across the network. The use of DTMF signals is a standard practice in many communication systems, allowing for efficient and straightforward access to services like IRLP.

Other options, such as obtaining a password sent via voice or entering an internet password, do not accurately represent how access is granted to the nodes in this specific scenario, as they suggest processes that aren't associated with typical DTMF operation. Likewise, CTCSS tone codes, while useful in analog radio systems to prevent interference and establish discrete communication, are not the means through which IRLP node access is gained.