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CTCSS/DCS codes ("Privacy" codes)

When using an FRS or GMRS radio (and some others), sometimes you can use a squelching technique to help with interference and extra noise (such as post-transmission noise). This is typically marketed as some form of "privacy" code but despite that, your transmission can be heard by anyone using the same frequency (channel) as you.

If a radio receives a signal on a sub-channel (i.e. only activates for a specific CTCSS/DCS code) and someone else is transmitting on a different code, you end up with a noisy interfered signal. You can respond by changing your channel or by ignoring the interference and continuing to transmit anyway -- but you probably shouldn't do that. Alternatively, you can say hi to your new friends by switching off CTCSS/DCS.

📻 Other FRS, GMRS, and ham radio pages

CTCSS codes

CTCSS (Continuous Tone-Coded Squelch System) is a technique where one low-frequency tone is broadcast with your audio. Receiving radios configured to a code will not turn on the speaker if it doesn't hear the code's tone over the air. Typically, a CTCSS aware receiver will strip out the tone.

The following codes should work on most FRS radios ("walkie-talkies") and the frequencies should work on most GMRS radios. DCS codes (see below) typically have higher sub-code numbers than CTCSS codes do, although sometimes a radio will have only one of CTCSS or DCS, or have them separated.

This list includes 38 codes and their corresponding frequencies. If you see 60 codes or less (typically around 40), your radio only supports CTCSS. If your radio has 121 or 38 codes, this list should be correct for the first 38.

1: 67.0 Hz
2: 71.9 Hz
3: 74.4 Hz
4: 77.0 Hz
5: 79.7 Hz
6: 82.5 Hz
7: 85.4 Hz
8: 88.5 Hz
9: 91.5 Hz
10: 94.8 Hz
11: 97.4 Hz
12: 100.0 Hz (not used in 50 Hz regions)
13: 103.5 Hz
14: 107.2 Hz
15: 110.9 Hz
16: 114.8 Hz
17: 118.8 Hz
18: 123.0 Hz
19: 127.3 Hz
20: 131.8 Hz
21: 136.5 Hz
22: 141.3 Hz
23: 146.2 Hz
24: 151.4 Hz
25: 156.7 Hz
26: 162.2 Hz
27: 167.9 Hz
28: 173.8 Hz
29: 179.9 Hz
30: 186.2 Hz
31: 192.8 Hz
32: 203.5 Hz
33: 210.7 Hz
34: 218.1 Hz
35: 225.7 Hz
36: 233.6 Hz
37: 241.8 Hz
38: 250.3 Hz
Some NATO military radios include a 150.0 Hz CTCSS tone.

Motorola Private Line codes (1Z, ZA, 2B, M7, etc)

Complete list of CTCSS frequencies

DCS codes

DCS (digital code squelching) uses a three-octal (that is, 000 to 777, or three bits) digital code transmitted at a low frequency in your audio. Apart from that, it functions pretty much identical to CTCSS.

This list includes the with-CTCSS and without-CTCSS "privacy codes", in that order, followed by the digital information represented as octals. If your radio has 121 or 83 codes, this list should be correct for it, but if it doesn't, check for the brand below.

39/1: 023
40/2: 025
41/3: 026
42/4: 031
43/5: 032
44/6: 043
45/7: 047
46/8: 051
47/9: 054
48/10: 065
49/11: 071
50/12: 072
51/13: 073
52/14: 074
53/15: 114
54/16: 115
55/17: 116
56/18: 125
57/19: 131
58/20: 132
59/21: 134
60/22: 143
61/23: 152
62/24: 155
63/25: 156
64/26: 162
65/27: 165
66/28: 172
67/29: 174
68/30: 205
69/31: 223
70/32: 226
71/33: 243
72/34: 244
73/35: 245
74/36: 251
75/37: 261
76/38: 263
77/39: 265
78/40: 271
79/41: 306
80/42: 311
81/43: 315
82/44: 331
83/45: 343
84/46: 346
85/47: 351
86/48: 364
87/49: 365
88/50: 371
89/51: 411
90/52: 412
91/53: 413
92/54: 423
93/55: 431
94/56: 432
95/57: 445
96/58: 464
97/59: 465
98/60: 466
99/61: 503
100/62: 506
101/63: 516
102/64: 532
103/65: 546
104/66: 565
105/67: 606
106/68: 612
107/69: 624
108/70: 627
109/71: 631
110/72: 632
111/73: 654
112/74: 662
113/75: 664
114/76: 703
115/77: 712
116/78: 723
117/79: 731
118/80: 732
119/81: 734
120/82: 743
121/83: 754

Other sub-codes

Some radios use a different set of codes. Consult your manual for more details.

📟 Different codes for Brand Name (TODO)