Ok,  I have see data from ecu with a 'like' of hyperterminal. I can see several sequences with a bit of loss. I will try to work with these data.
data from site
312F603CE410004000000000004000000042C0555
local data
3ieme test struc '3'
=310F4038D4F000400D50000000400000004DF
=310F4038D4F000400000000000000000004DF
=310F4038D4F004030000000400400000004DF
=30004038D4F000432000000000400000004DF
=31000034B4F00040DF400000000000000049D
=310F4034B4F00003D0000000004000000049D
4ieme test struc '3'
=312A303F44E000000000000000400000 0444
=332A403084F00040000000000000047D 045A
=332A403084F0004000000000004000000045A
=332A403084F0004000000000000000000045A
=312A503084F00040000000000000047D 045A
=310F403084F0000000000400004000000045A
=3121403084F0004000000000000000000045Ae

3ieme test struc '0'
=0000401D7020E030D033B00C6F03601E9
=0000001D7020E000D033B00C601320101
=00E7301D6020E000D033B00C601650166
=0007B01D6020E039E033B00C600330176
=00E8301D6020E039DB03B00C600330186
=00E8B01 6020E001D033B0036017D0196
4ieme test struc '0'
=00ED201D4020E03B0033B00C00DC80125
=00DF501D4020E03B0033B00C5014B012B
=00DD701D402E0339E033B00C501CD012F
=00DE801D502E0339E0BF01750082 0133
=00EE021D4020E03B0033B00C00BD20137
=00DEB01D5020E039E0C3000C401D30139
=00DDF01D0320E039D0C301CB0035 0140
=00DD001D40200339E033B0DE001D80143