4S6TMP.com — All 52 PL tones & 104 DCS codes with audio generator
| Tone (Hz) | Motorola Code | Common Use |
|---|---|---|
| 67.0 | XZ | Very common in Europe |
| 71.9 | XZA | European repeaters |
| 74.4 | WZA | Less common |
| 77.0 | WZ | Common in US |
| 79.7 | WZA | Some US repeaters |
| 82.5 | XZ | Very common worldwide |
| 85.4 | — | Less common |
| 88.5 | — | Common in US |
| 91.5 | — | Common in US |
| 94.8 | — | Common in US |
| 97.4 | — | Common in US |
| 100.0 | — | Very common worldwide |
| 103.5 | — | Very common worldwide |
| 107.2 | — | Common in US |
| 110.9 | — | Common in US |
| 114.8 | — | Common in US |
| 118.8 | — | Common in US |
| 123.0 | — | Very common worldwide |
| 127.3 | — | Very common worldwide |
| 131.8 | — | Common in US |
| 136.5 | — | Common in US |
| 141.3 | — | Common in US |
| 146.2 | — | Common in US |
| 151.4 | — | Common in US |
| 156.7 | — | Very common worldwide |
| 162.2 | — | Common in US |
| 167.9 | — | Common in US |
| 173.8 | — | Common in US |
| 179.9 | — | Common in US |
| 186.2 | — | Common in US |
| 192.8 | — | Common in US |
| 203.5 | — | Common in US |
| 210.7 | — | Common in US |
| 218.1 | — | Common in US |
| 225.7 | — | Common in US |
| 233.6 | — | Common in US |
| 241.8 | — | Common in US |
| 250.3 | — | Common in US |
CTCSS (Continuous Tone-Coded Squelch System), also known as PL (Private Line, a Motorola trademark), is a method of using a sub-audible tone to control repeater access and reduce interference. The tone is transmitted along with your voice signal but is filtered out before reaching the speaker, so you don't hear it.
When a repeater receives a signal with the correct CTCSS tone, it retransmits it. Without the correct tone, the repeater ignores the signal. This prevents random noise, distant stations, or interfering signals from keying up the repeater.
DCS (Digital-Coded Squelch), also known as DPL (Digital Private Line, another Motorola trademark), uses a digital code instead of an analog tone. It offers more codes (104 vs. 52) and better immunity to false triggering from voice frequencies that happen to contain CTCSS tones.
DCS codes come in "Normal" (N) and "Inverted" (I) variants. Most ham radios use the Normal variant. The inverted variant is sometimes used in commercial systems.
The tone generator uses your browser's Web Audio API to produce the exact CTCSS frequency. This is useful for:
Note: Most speakers and headphones can reproduce CTCSS tones (67–254 Hz), but some small laptop speakers may not. Use headphones for best results.
Why does my radio show different codes for the same frequency? Different manufacturers use different naming schemes. Motorola uses "PL" codes like "PL 123.0" or "PL 77.0". Icom uses numbers like "Tone 8" or "Tone 16". Yaesu uses the frequency directly. The frequency is what matters — the code name is just a label.
Can I use CTCSS on simplex? Yes, but it's less common. Some operators use CTCSS on simplex frequencies to avoid hearing distant interference. Both stations must use the same tone.
What's the difference between CTCSS Encode and Decode? Encode means your radio transmits the tone. Decode means your radio only opens the squelch when it receives the correct tone. For repeater operation, you need encode enabled. For simplex with tone squelch, both stations need encode and decode enabled.