Glossary and terms

Revision history DateDescription 2013-12-01 Initial version. 2013-12-20 More stuff added. 2014-02-02 Even more stuff added.

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Appendix. Semantics of the Pronto CCF format.

An IR signal in Pronto CCF form consists of a number of 4-digit hexadecimal numbers. For example:

0000 006C 0022 0002 015B 00AD 0016 0041 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0041 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0041 0016 0041 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0041 0016 0041 0016 0041 0016 0041 0016 0041 0016 0041 0016 06FB 015B 0057 0016 0E6C

The first number, here 0000, denotes the type of the signal. 0000 denotes a raw IR signal with modulation, while 0100 denotes a non-modulated raw IR signal. There are also a small number of other allowed values, denoting signals in protocol/parameter form, notably 5000 for RC5-protocols, 6000 for RC6-protocols, and 900A for NEC1-protocols.

The second number, here 006C, denotes a frequency code. For the frequency f in Hertz, this is the number 1000000/(f*0.241246) expressed as a four-digit hexadecimal number. In the example, 006C corresponds to 1000000/(0x006c * 0.241246) = 38381 Hertz. (It can be conveniently computed by the Time/Frequency Calculator in IrScrutinizer, available under the Tools menu.)

The third and the forth number denote the number of pairs (= twice the number of durations) in the start- and the repeat sequence respectively. In the example, there are 0x0022 = 34 starting pairs, and 2 repeat pairs.

Next the start- and the repeat-sequences follow; their length being given by the third and the forth number, as per above. The numbers therein are all time durations, the ones with odd numbers on-periods, the other ones off-periods. These are all expressed as multiples of the period time; the inverse value of the frequency given through the second number. For this reason, "frequency" must be a sensible number also for the non-modulated case, denoted by the first number being 0100. In the example, the fifth number 0x015B denotes an on-period of 0x015B*periodtime = 347/f = 347/38381 = 0.009041 seconds.

In particular, all sequences start with an on-period and end with an off-period.

In the Pronto representation, there is no way to express an ending sequence.