CTCSS (Continuous Tone Coded Squelch System)

CTCSS (Continuous Tone Controlled Squelch System) a sub audible tone in the range of 67 to 254 Hz. The FM deviation level of CTCSS tones should be in the range of 500 to 800 Hz. These tones are encoded with the voice audio at all times during the transmission. Any one or more of the 50 tones can be used to gain access to the repeater. CTCSS decode and encode is provided as a standard feature on all of our controllers, using state of the art devices. All standard and non standard EIA CTCSS tones can be decoded or encoded. You may select 1, 2, 3 or up to all 50 CTCSS decode tones to operate the repeater. You can even use CTCSS tones and DCS codes on the same channel. We have also divided the CTCSS decode into six independent tone panels. This allows you to assign a different group of tones for different functions. These tone panels have the following functions:

Tone panel #1, Repeater operation (audio) only.
Tone panel #2, User commands.
Tone panel #3, System Commands (commands for programming the controller). This tone panel will also allow access of user commands.
Tone panel #4, Auxiliary output audio. Used when linking multiple controllers together.
Tone panel #5, Telephone audio. Used to access, dial and pass audio to the telephone interconnect.
Tone panel #6, Dial Click. Used for dial click commands, see S-Command 49.

The CTCSS encode deviation level can be adjusted up and down remotely over the air or telephone interconnect. The received or incoming CTCSS tones may be passed to the repeater transmitter, or filtered (removed with a high pass filter, with no tone going out to the repeater transmitter). Under normal conditions, you will filter out in incoming tone and re-encoding a new CTCSS tone either on the same or a selected different frequency.

The following is a table of standard and non-standard CTCSS tones used in our controllers.

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