DVDO VP50 PRO - Manual (Page 66)

NEC IR Code Format
Parameter
Carrier Frequency
Unit of Burst Time
Lead In Burst
"1" Burst Pattern
"0" Burst Pattern
Lead Out
Decimal Value
40kHz
22 cycles of the carrier
341 171
22 96
22 24
22, 1427
HEX Value
0156 00ab
0016 0060
0016 0016
0016 0593
Doing the arithmetic we see that this code uses a base time of 550 microseconds.
The lead in is a unique burst as is the lead out. It is a pulse width modulation system
where the information is carried in the length of the off time with a fixed duration of on
time. The NEC message format is quite a bit more complicated then that of Sony. It is
always a 32-bit code. Which consists of 16 bits of data and 16 bits of error checking.
The code is divided into four 8-bit fields.
Device Code Device code Compliment Function Code Function Code Compliment
A device code will be in the range of 0 to 255 or 256 discrete device codes. The
same is true of the function code. The compliment fields are the 1’s compliment of the
code they represent. The device code and the device code compliment must add up to 255
or else there is an error. The same is true of the function code and the function code
compliment. NEC uses a discrete lead in and a discrete lead out, so the total code length
will take 34 burst pairs to represent as a Burst Pair Sequence.
The following as an example of a Pioneer IR sequence for the CLD79 Elite Laser
Disk Player.
0000 0067 0000 0022 0156 00ab 0016 0060 0016 0060 0016
0060 0016 0016 0016 0060 0016 0016 0016 0060 0016 0016 0016
0016 0016 0016 0016 0016 0016 0060 0016 0016 0016 0060 0016
0016 0016 0060 0016 0060 0016 0016 0016 0060 0016 0016 0016
0016 0016 0060 0016 0060 0016 0060 0016 0016 0016 0060 0016
0016 0016 0060 0016 0060 0016 0016 0016 0016 0016 0016 0016
0593
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