Ending of "good" lines....

0x00002160: 20FE455F 44697361 FE456420 202020FE 
0x00002170: 45005368 757474FE 99670A

line 3
0x00002130: 3531DF46 2020FE45 50202020 06FE4514     51.F  .EP   ..E.
0x00002140: 486F7572 73203A20 32373639 20202020     Hours : 2769
0x00002150: 202020FE 45552020 2020FE45 5A202020        .EU    .EZ
0x00002160: 20FE455F 44697361 FE456420 202020FE      .E_Disa.Ed    .
0x00002170: 45005368 757474FE 99670A                E.Shutt..g.



202020FE 20FE455F 44697361 FE456420 202020FE 45005368 757474FE 99670A

line 4
5A202020 20FE455F 44697361 FE456420 202020FE 45005368 757474FE 99670A 


0x00002A40: 64202020 20FE4500 53687574 74FE9967     d    .E.Shutt..g
0x00002A50: 0A                                      .

0x00002A20: 36392020 20202020 20FE4555 20202020     69       .EU
0x00002A30: FE455A20 202020FE 455F4469 7361FE45     .EZ    .E_Disa.E
0x00002A40: 64202020 20FE4500 53687574 74FE9967     d    .E.Shutt..g
0x00002A50: 0A                 


This end pattern is common:
20FE455F 44697361 FE456420 202020FE 45005368 757474FE 99670A

grep -P "\x05\x00\xc0" mybinaryfile

grep -P "\x99\x67\x0A" big_furmon_data_sample_2103-03-15

20FE455F 44697361 \xFE\x45\x64\x20\x20\x20\x20\xFE\x45\x00\x53\x68\x75\x74\x74\xFE\x99\x67\x0A

grep -P "\xFE\x45\x64\x20\x20\x20\x20\xFE\x45\x00\x53\x68\x75\x74\x74\xFE\x99\x67\x0A" big_furmon_data_sample_2103-03-15

Line 3 beginning
0x00000000: 09924550 20202006 FE451453 74617274     ..EP   ..E.Start


Line 4 beginning
0x00000000: 09924550 20202006 FE451452 65736574     ..EP   ..E.Reset


This works:
grep -aiP "\x99\x67$" big_furmon_data_sample_2103-03-15 | most

common beginning:

09924550 20202006 FE4514

grep -aiP "\x09\x92\x45\x50\x20\x20\x20\x06\xFE\x45\x14" big_furmon_data_sample_2103-03-15

This pattern works:
grep -aiP "^\x09\x92\x45\x50\x20\x20\x20\x06\xFE\x45\x14" big_furmon_data_sample_2103-03-15 | most

grep -aiP "^\x09\x92\x45\x50\x20\x20\x20\x06\xFE\x45\x14" big_furmon_data_sample_2103-03-15 > data.cleaned

to see lengths of line...
n=1; cat data.cleaned|while read line; do echo -e \\t $(( n ++ )) \\t $(echo $line |wc -c ); done | less


<input_file python -c '
  import sys
  n = ord(sys.stdin.read(1))      # read length byte
  s = sys.stdin.read(n)           # read data
  if len(s) < n: raise ValueError("input file too short")
  # Process s here
'

import sys
fin = open('data.cleaned','rb')
while fin
while fin != ""
 s = fin.read()
 print len(s)


# http://stackoverflow.com/questions/1035340/reading-binary-file-in-python
f = open("data.cleaned", "rb")
try:
    byte = f.read(1)
    while byte != "":
        # Do stuff with byte.
        print byte
        byte = f.read(1)
finally:
    f.close()

# do it with a line...
f = open("data.cleaned", "rb")
n = 1
try:
    line = f.readline()
    while line != "":
        # Do stuff with byte.
        #print len(line)
        print "%d  %d" % ((n += 1),len(line))
        line = f.readline()
finally:
    f.close()