Why does type-mask -2 Work?

Alot of people have suggested using a type-mask of -2. This may work and enable all options I am pretty sure its not the "correct" way of doing it.

So why does type-mask -2 work?

Well in theory -1111101(-2) which = 0111101 (61) if you use the 7th bit as the signed bit.

So if you set yout config file to 61 instead of -2 it will enable Tethering,MMS,Data (and no Voicemail) which is what we are seeing with -2

Comments?

just to note: no Official IPCC file uses negative numbers..
only bits 1->6 for Options.

Well.. it is the way nagative binary works..

0 0000000
1 0000001
2 0000010
4 0000100
8 0001000
16 0010000
32 0100000
33 0100001
...
63 0111111
-63 1000000
-62 1000001
-61 1000010
-60 1000011
-59 1000100
-58 1000101
-57 1000110
-56 1000111
-55 1001000
-54 1001001
-53 1001010
-52 1001011
-51 1001100
-50 1001101
-49 1001110
-48 1001111
-47 1010000
-46 1010001
-45 1010010
-44 1010011
-43 1010100
-42 1010101
-41 1010110
-40 1010111
-39 1011000
-38 1011001
-37 1011010
-36 1011011
-35 1011100
-34 1011101
-33 1011110
-32 1011111
-31 1100000
-30 1100001
-29 1100010
-28 1100011
-27 1100100
-26 1100101
-25 1100110
-24 1100111
-23 1101000
-22 1101001
-21 1101010
-20 1101011
-19 1101100
-18 1101101
-17 1101110
-16 1101111
-15 1110000
-14 1110001
-13 1110010
-12 1110011
-11 1110100
-10 1110101
-09 1110110
-08 1110111
-07 1111000
-06 1111001
-05 1111010
-04 1111011
-03 1111100
-02 1111101
-01 1111110
-00 1111111