I have a GPS Tracker that connects and send data to a defined public server: port through GPRS connection. I am getting the result on the terminal.

I have provided with a manual. I don't understand one part where I need the help of you that's why I came here.

I received vehicle status value like this FFF7BBFF.And the manual says about this value is enter image description here

I do not quite understand how to use it. Do you guys have an idea ?. Please anyone can explain to me and help me to translate this code FFF7BBFF

  • \$\begingroup\$ any zero bit means that the bit is active .... example 2nd byte ... F7= 1111 0111 .... bit3 = 0 (active) .... terminal by backup battery power supply ................. BB = 1011 1011 .... custom alarm ... acc off \$\endgroup\$ – jsotola May 8 '18 at 16:24
  • \$\begingroup\$ Do you know how to convert between bases? \$\endgroup\$ – Eugene Sh. May 8 '18 at 16:24
  • \$\begingroup\$ @jsotola Thank you very much but I am really sorry I still couldn't be able to understand you. can we chat somewhere? \$\endgroup\$ – user1hjgjhgjhggjhg May 8 '18 at 16:29
  • \$\begingroup\$ The table could be very misleading, as conventionally bit sequence is read left-to-right and numbered in decrescent fashion. The table is top-down and numbered in crescent fashion. Things like 'first byte' should read MSB or LSB (most/least significant byte). Anyway, the keywords you are looking for are 'hexadecimal base' and 'binary base'. \$\endgroup\$ – Vicente Cunha May 8 '18 at 16:31
  • \$\begingroup\$ It doesn’t matter whether you use ASCII or hex either method still requires conversion to binary which is shown in the table above. Hex is better because some codes have no ASCII visible character \$\endgroup\$ – Sunnyskyguy EE75 May 8 '18 at 16:36

First, split FFF7BBFF into four bytes: FF-F7-BB-FF

Each byte corresponds to a column in your table. If it was written like any normal documentation I would say "the first byte" is on the right. However, taking into account unconventional presentation, all bets are off. In fact, it looks like they number bytes left-to-right (see below).

Second, convert hexadecimal presentation into binary, for example your "BB" becomes "10111011". I won't be explaining how to do it here, this is not the right place for basic things children learn in school.

Third, compare each bit to corresponding byte column, with right-most bit (hopefully) being bit #0 (top row). For example, if you compare "10111011" to "the third byte" column you would see that two states are "effective" i.e. equal to zero: #2 (ACC Off) and #6 (Custom alarm).

The fact that bit #3 of this column is supposed to be 1 all the time ("reserves"?!) and bit 3 of F7 is not, tells me they indeed number bytes left-to-right.


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