After some time spent on it, finally I found something that works.
I have recorded a long pattern of from the IC composed as follow:
20 HDLC flag (0x7E) + 10 bytes of random data set from the Programming User interface of the chip. Then I enabled the FEC correction.
Analysing the acquisition I found a repetitive pattern, after some initial bytes, that I think it represents the HDLC flag convolved. The message recorded is exactly doubled in time respect the same message without the FEC enabled-
The interesting part is that, with gnuradio native blocks for convolutional decoder definition I can’t retrieve the initial sequence, I think that it can not work with a constraint length of 5, but nevermind, I built my own convolutional decoder and it works.
My current gnuradio version is the 3.7.9. Do you have any council for me regarding the native Convolutional decoding block from gnuradio and why should it not work with these parameters?
After that, I have enabled the Interleaving option and made another recording but this time even if the initial sequence is still repetitive it does not any sense for me
Can you please give me some information about the interleaving?