How is over the air access to Internet Radio Linking Project (IRLP) nodes accomplished?

Question

Accepted Answer

B. By using Dual-Tone Multi-Frequency (DTMF) signals Over-the-air access to IRLP nodes uses DTMF (Dual-Tone Multi-Frequency) signals. These are the touch-tone sounds your radio's keypad sends. CTCSS tones only open a repeater's squelch; they don't select a node.