IC-R20 Tone Squelch, DTCS, Pocket Beep & Tone Scan

Summary: How to use the IC-R20’s tone squelch, DTCS squelch, pocket beep and Voice Squelch Control, and how to find an unknown tone.

Tone Squelch, DTCS and Pocket Beep

The tone or DTCS squelch opens only when the signal carries the matching subaudible tone or DTCS code, so you can wait silently for it. Set the frequency in FM mode and, while pushing [7 TONE], rotate [R-DIAL] to choose:

• TSQL – tone squelch
• TSQLS – tone squelch with pocket beep
• DTCS – DTCS squelch
• DTCSS – DTCS with pocket beep
• VSC – Voice Squelch Control
• OFF (no indicator)

With pocket beep, a matching signal opens the squelch and also sounds beep tones and blinks “S” for about 30 seconds. Push [DUALWATCH] to stop them (which also deactivates pocket beep). To cancel the tone squelch rotate [R-DIAL] while pushing [7 TONE] until the indicator disappears. Holding [7 TONE] for 1 second also steps through the same list.

Voice Squelch Control (VSC)

VSC opens the squelch only when a modulated signal is received. It’s very useful while scanning, because scans pause only on modulated signals and continue past unmodulated or beat signals.

Setting the Tone Frequency or DTCS Code

Defaults: 88.5 Hz and DTCS code 023. In the expanded set mode choose TONE FREQ or DTCS CODE and select. The receiver has 50 tone frequencies, closer together than on 38-tone radios, so adjacent tones can interfere with each other. DTCS polarity (NORMAL or REVERSE) is set in DTCS POLARITY: with the wrong polarity DTCS never unmutes.

Tone frequencies (Hz): 67.0, 69.3, 71.9, 74.4, 77.0, 79.7, 82.5, 85.4, 88.5, 91.5, 94.8, 97.4, 100.0, 103.5, 107.2, 110.9, 114.8, 118.8, 123.0, 127.3, 131.8, 136.5, 141.3, 146.2, 151.4, 156.7, 159.8, 162.2, 165.5, 167.9, 171.3, 173.8, 177.3, 179.9, 183.5, 186.2, 189.9, 192.8, 196.6, 199.5, 203.5, 206.5, 210.7, 218.1, 225.7, 229.1, 233.6, 241.8, 250.3, 254.1.

DTCS codes (104, 023-754): 023, 025, 026, 031, 032, 036, 043, 047, 051, 053, 054, 065, 071, 072, 073, 074, 114, 115, 116, 122, 125, 131, 132, 134, 143, 145, 152, 155, 156, 162, 165, 172, 174, 205, 212, 223, 225, 226, 243, 244, 245, 246, 251, 252, 255, 261, 263, 265, 266, 271, 274, 306, 311, 315, 325, 331, 332, 343, 346, 351, 356, 364, 365, 371, 411, 412, 413, 423, 431, 432, 445, 446, 452, 454, 455, 462, 464, 465, 466, 503, 506, 516, 523, 526, 532, 546, 565, 606, 612, 624, 627, 631, 632, 654, 662, 664, 703, 712, 723, 731, 732, 734, 743, 754.

Tone Scan

1. Tune to the signal and turn on TSQL or DTCS (by holding [7 TONE] and rotating).
2. Hold [4 T-SCAN] for 1 second. Rotate [R-DIAL] to change direction.
3. When a CTCSS tone or three-digit DTCS code matches, the squelch opens and the tone or code is temporarily programmed into the selected condition (for example the memory channel). Even with no tone type selected, holding [4 T-SCAN] scans for tones.

The decoded tone is temporary: it’s cleared when you re-select the memory channel, so store it (see IC-R20 Memory Channels & Banks). Pocket beep is cancelled when a tone scan starts.