CCITT

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CCITT
Ccitt 5-tones.jpg
Frequencies 30 MHzMegaHertz (MHz) 10^6 Hz30,000,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
30,000 kHzKiloHertz (kHz) 10^3 Hz
,800 MHzMegaHertz (MHz) 10^6 Hz800,000,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
800,000 kHzKiloHertz (kHz) 10^3 Hz
30,000 kHzKiloHertz (kHz) 10^3 Hz
30 MHzMegaHertz (MHz) 10^6 Hz
800,000 kHzKiloHertz (kHz) 10^3 Hz
800 MHzMegaHertz (MHz) 10^6 Hz
Frequency Range 30 MHzMegaHertz (MHz) 10^6 Hz30,000,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
30,000 kHzKiloHertz (kHz) 10^3 Hz
- 800 MHzMegaHertz (MHz) 10^6 Hz800,000,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
800,000 kHzKiloHertz (kHz) 10^3 Hz
Mode NFMNarrowband Frequency Modulation
Modulation MFSKMultiple Frequency Shift-Keying
ACF
Bandwidth 5 kHzKiloHertz (kHz) 10^3 Hz5,000 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz).
0.005 MHzMegaHertz (MHz) 10^6 Hz
kHzKiloHertz (kHz) 10^3 Hz
0.005 MHzMegaHertz (MHz) 10^6 Hz
kHzKiloHertz (kHz) 10^3 Hz
0.005 MHzMegaHertz (MHz) 10^6 Hz
Location Worldwide
Short Description CCITT is a 5-tone selcall system for VHFVery High Frequency (30-300 MHz)/UHFUltra High Frequency (300-3000 MHz) radios.
I/Q Raw Recording
Audio Sample
CCITT is a 15 tone selcall system for VHFVery High Frequency (30-300 MHz)/UHFUltra High Frequency (300-3000 MHz) radios. CCITT stands for Comité Consultatif International Téléphonique et Télégraphique, which has now become the ITU-T.

Selcall (selective calling) is a type of squelch protocol used in radio communications systems, in which transmissions include a brief burst of sequential audio tones. Receivers that are set to respond to the transmitted tone sequence will open their squelch, while others will remain muted.

CCITT has 100 msmilliseconds (.001 of a second) tone duration per tone. Each tone corresponds with either a number or letter, as denoted by the table below. CCITT has 15 tones to choose from, but only sends a burst of up to 5 tones. The bursts transmit right before a radio transmission.


CCITTTable.png

Samples[edit]

Full Range 5-tone Burst
CCITT.jpg
Ccitt 5-tones.jpg

Decoding Software[edit]

Hobby Level Software

Video Examples[edit]

Additional Links[edit]

Additional Images[edit]