🔍 Key Concepts

• CTCSS (Continuous Tone-Coded Squelch System) purpose in radios • Difference between noise squelch and tone/code squelch • How receivers decide when to unmute (open) the speaker

💭 Think About

• Ask yourself: does CTCSS depend on random background noise, or on something intentionally added to the transmitted signal? • Think about what is actually sent along with the voice audio so that only selected radios open their squelch. • Which option describes a continuous, low-frequency element that riding under the voice, rather than a one-time digital handshaking process?

✅ Before You Answer

• Verify that CTCSS is an analog system used with FM radios, not a digital signaling scheme. • Confirm that CTCSS works by sending a continuous signal component below the normal voice frequency range. • Eliminate any choices that describe general background noise instead of a specific, added control signal.