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Trimble 4000 Option Codes

Enabling Options

Entering Option Codes

1. Push the MODIFY button
2. Using the numeric keypad, enter 567355 (spells OPTION)
3. Enter the option code and follow the steps.

Generating Option Codes

First make a plaintext option code in this format:

SSSSSNNVV

SSSSS = Serial number in base 10, padded with leading zeros

NN = Option number in base 10 (see below), padded with leading zeros

VV = Option value in hexadecimal, padded with leading zeros. Usually 00 to enable a feature, and FF to disable it.

For example, for a receiver with serial number 12345, to enable Option 25 (1 PPS) (value = 0x00), the plaintext option code would be:

123452500

Now to encrypt it:

1. Reverse the order of the bits for each nibble in the plaintext option code (i.e. 0100 becomes 0010, 1011 becomes 1101, etc.):

   123452500 becomes 84C2A4A00

2. XOR each nibble with the last 4 bits of the serial number (in this case, 0x9:

   84C2A4A00 ^ 999999999 = 1D5B3D399

3. XOR that value with with 0x241895577

   1D5B3D399 ^ 241895577 = 3943A86EE

4. Now reverse the order of the nibbles:

   3943A86EE becomes EE68A3493

5. And finally, slap on a checksum (in hex) at the end: (the number of binary 1s in the code) modulo 4. In this case:

   3943A86EE = 001110010100001110101000011011101110

   Number of 1s = 18, 18 % 16 = 2. Our checksum is 2.

   EE68A3493 becomes EE68A34932

And we’re done. The encrypted code is EE68A34932

Option Numbers: