Transponder Gray Code (Gillham Code) Reference

Transponder Gray Code (Gillham Code) Reference

This reference shows the Gray Code output of an altitude encoder (including the gray code outputs on all MGL Avionics equipment that outputs it). This can be used to trouble shoot harnesses and encoders. Some transponders will display the gray code they are receiving and testing equipment can be used to see which of the switches are working in the parallel Gray Code output.

The first digits are the altitude in feet and the second string of digits are the Gillham code outputs represented as 0's and 1's. 

The numbers are in this order: D1, D2, D4, A1, A2, A4, B1, B2, B4, C1, C2, C4.

         DDDAAABBBCCC 
ALT     124124124124 

-1200 000000000001 
-1100 000000000011 
-1000 000000000010 
-900 000000000110 
-800 000000000100 
-700 000000001100 
-600 000000001110 
-500 000000001010 
-400 000000001011 
-300 000000001001 
-200 000000011001 
-100 000000011011 
0 000000011010 
100 000000011110 
200 000000011100 
300 000000010100 
400 000000010110 
500 000000010010 
600 000000010011 
700 000000010001 
800 000000110001 
900 000000110011 
1000 000000110010 
1100 000000110110 
1200 000000110100 
1300 000000111100 
1400 000000111110 
1500 000000111010 
1600 000000111011 
1700 000000111001 
1800 000000101001 
1900 000000101011 
2000 000000101010 
2100 000000101110 
2200 000000101100 
2300 000000100100 
2400 000000100110 
2500 000000100010 
2600 000000100011 
2700 000000100001 
2800 000001100001 
2900 000001100011 
3000 000001100010 
3100 000001100110 
3200 000001100100 
3300 000001101100 
3400 000001101110 
3500 000001101010 
3600 000001101011 
3700 000001101001 
3800 000001111001 
3900 000001111011 
4000 000001111010 
4100 000001111110 
4200 000001111100 
4300 000001110100 
4400 000001110110 
4500 000001110010 
4600 000001110011 
4700 000001110001 
4800 000001010001 
4900 000001010011 
5000 000001010010 
5100 000001010110 
5200 000001010100 
5300 000001011100 
5400 000001011110 
5500 000001011010 
5600 000001011011 
5700 000001011001 
5800 000001001001 
5900 000001001011 
6000 000001001010 
6100 000001001110 
6200 000001001100 
6300 000001000100 
6400 000001000110 
6500 000001000010 
6600 000001000011 
6700 000001000001 
6800 000011000001 
6900 000011000011 
7000 000011000010 
7100 000011000110 
7200 000011000100 
7300 000011001100 
7400 000011001110 
7500 000011001010 
7600 000011001011 
7700 000011001001 
7800 000011011001 
7900 000011011011 
8000 000011011010 
8100 000011011110 
8200 000011011100 
8300 000011010100 
8400 000011010110 
8500 000011010010 
8600 000011010011 
8700 000011010001 
8800 000011110001 
8900 000011110011 
9000 000011110010 
9100 000011110110 
9200 000011110100 
9300 000011111100 
9400 000011111110 
9500 000011111010 
9600 000011111011 
9700 000011111001 
9800 000011101001 
9900 000011101011 
10000 000011101010 
10100 000011101110 
10200 000011101100 
10300 000011100100 
10400 000011100110 
10500 000011100010 
10600 000011100011 
10700 000011100001 
10800 000010100001 
10900 000010100011 
11000 000010100010 
11100 000010100110 
11200 000010100100 
11300 000010101100 
11400 000010101110 
11500 000010101010 
11600 000010101011 
11700 000010101001 
11800 000010111001 
11900 000010111011 
12000 000010111010 
12100 000010111110 
12200 000010111100 
12300 000010110100 
12400 000010110110 
12500 000010110010 
12600 000010110011 
12700 000010110001 
12800 000010010001 
12900 000010010011 
13000 000010010010 
13100 000010010110 
13200 000010010100 
13300 000010011100 
13400 000010011110 
13500 000010011010 
13600 000010011011 
13700 000010011001 
13800 000010001001 
13900 000010001011 
14000 000010001010 
14100 000010001110 
14200 000010001100 
14300 000010000100 
14400 000010000110 
14500 000010000010 
14600 000010000011 
14700 000010000001 
14800 000110000001 
14900 000110000011 
15000 000110000010 
15100 000110000110 
15200 000110000100 
15300 000110001100 
15400 000110001110 
15500 000110001010 
15600 000110001011 
15700 000110001001 
15800 000110011001 
15900 000110011011 
16000 000110011010 
16100 000110011110 
16200 000110011100 
16300 000110010100 
16400 000110010110 
16500 000110010010 
16600 000110010011 
16700 000110010001 
16800 000110110001 
16900 000110110011 
17000 000110110010 
17100 000110110110 
17200 000110110100 
17300 000110111100 
17400 000110111110 
17500 000110111010 
17600 000110111011 
17700 000110111001 
17800 000110101001 
17900 000110101011 
18000 000110101010 
18100 000110101110 
18200 000110101100 
18300 000110100100 
18400 000110100110 
18500 000110100010 
18600 000110100011 
18700 000110100001 
18800 000111100001 
18900 000111100011 
19000 000111100010 
19100 000111100110 
19200 000111100100 
19300 000111101100 
19400 000111101110 
19500 000111101010 
19600 000111101011 
19700 000111101001 
19800 000111111001 
19900 000111111011 
20000 000111111010 
20100 000111111110 
20200 000111111100 
20300 000111110100 
20400 000111110110 
20500 000111110010 
20600 000111110011 
20700 000111110001 
20800 000111010001 
20900 000111010011 
21000 000111010010 
21100 000111010110 
21200 000111010100 
21300 000111011100 
21400 000111011110 
21500 000111011010 
21600 000111011011 
21700 000111011001 
21800 000111001001 
21900 000111001011 
22000 000111001010 
22100 000111001110 
22200 000111001100 
22300 000111000100 
22400 000111000110 
22500 000111000010 
22600 000111000011 
22700 000111000001 
22800 000101000001 
22900 000101000011 
23000 000101000010 
23100 000101000110 
23200 000101000100 
23300 000101001100 
23400 000101001110 
23500 000101001010 
23600 000101001011 
23700 000101001001 
23800 000101011001 
23900 000101011011 
24000 000101011010 
24100 000101011110 
24200 000101011100 
24300 000101010100 
24400 000101010110 
24500 000101010010 
24600 000101010011 
24700 000101010001 
24800 000101110001 
24900 000101110011 
25000 000101110010 
25100 000101110110 
25200 000101110100 
25300 000101111100 
25400 000101111110 
25500 000101111010 
25600 000101111011 
25700 000101111001 
25800 000101101001 
25900 000101101011 
26000 000101101010 
26100 000101101110 
26200 000101101100 
26300 000101100100 
26400 000101100110 
26500 000101100010 
26600 000101100011 
26700 000101100001 
26800 000100100001 
26900 000100100011 
27000 000100100010 
27100 000100100110 
27200 000100100100 
27300 000100101100 
27400 000100101110 
27500 000100101010 
27600 000100101011 
27700 000100101001 
27800 000100111001 
27900 000100111011 
28000 000100111010 
28100 000100111110 
28200 000100111100 
28300 000100110100 
28400 000100110110 
28500 000100110010 
28600 000100110011 
28700 000100110001 
28800 000100010001 
28900 000100010011 
29000 000100010010 
29100 000100010110 
29200 000100010100 
29300 000100011100 
29400 000100011110 
29500 000100011010 
29600 000100011011 
29700 000100011001 
29800 000100001001 
29900 000100001011 
30000 000100001010 
30100 000100001110 
30200 000100001100 
30300 000100000100 
30400 000100000110 
30500 000100000010 
30600 000100000011 
30700 000100000001 
30800 001100000001 
SNIP This sequence continues thru D4 & D2 up to 126,700' 

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