ARRL Technician Practice Exam

How is access to an IRLP node accomplished?

1. By dialing a telephone number

2. By using DTMF signals

3. By sending an email request

4. By connecting via satellite

The correct answer is: By using DTMF signals

Access to an IRLP (Internet Radio Linking Project) node is accomplished primarily using DTMF (Dual-Tone Multi-Frequency) signals. This system allows amateur radio operators to connect to an IRLP node by sending specific DTMF tones through their radio transceiver. When a user sends these tones, they act as commands that the IRLP node recognizes, enabling the connection to other nodes or allowing access to different audio streams. While other methods such as dialing a telephone number might be applicable in different contexts within telecommunications, it is DTMF tones that are specifically designed for control and signaling in radio communications, making them the appropriate choice for accessing an IRLP node. The use of DTMF provides a straightforward method to initiate and control connections without requiring additional communication methods, such as email or satellite connection, which are not relevant for accessing IRLP nodes.