### Royal Festival Hall condundrum

When I went to record Shift Run Stop at the Royal Festival Hall a few weeks ago I noticed that the display on the 5th floor lift was not showing 5 but a bit pattern. I snapped a quick photo and decided to look into it later:

And here's a close up of the top of it.

If you look carefully you'll see that there are 8 columns of on or off squares. I transcribed the squares with on = 1 and off = 0 to get the following list: 11111111 11000100 11011000 11101100 00000000 00010100 00101000 01001110 01110100 10001000 10011100 10110000 11000100 11011000 11101100 00000000 00010100 00101000 00111100 01010000 01100100 01111000 10001100 10100000 10110100 11001000 11011100 11110000 00000100 00011000 00101100 01000000 01010100 01101110 10001110 10110100 11001000 11101110 00000010 00010110 00101010 01010000 01111000 10001100 10110010 11001110 11101100 00000000 00100110 00111010 01100000 10000110 10011010 11000000 11010100 11111010 00100000 01001100 01101100 10000000 10010100 10101000 10111100 11010000 11100100 11111000 00001100 00110110.

Apart from the first item which is all 1s all the others have a right-most bit of zero. At first I thought this might be 7-bit ASCII (LSB first), but decoding that just gives a mess. Then I wondered if it was machine code, but I think that's unlikely given the fact that one of the bits is always zero. I don't think this is random data.

Here it is as hex with LSB on the right.
`ff c4 d8 ec 00 14 28 4e 74 88 9c b0 c4 d8 ec 00 14 28 3c 50 64 78 8c a0 b4 c8 dc f0 04 18 2c 40 54 6e8e b4 c8 ee 02 16 2a 50 78 8c b2 ce ec 00 26 3a 60 86 9a c0 d4 fa 20 4c 6c 80 94 a8 bc d0 e4 f8 0c 36`

And reversed:
`ff 23 1b 37 00 28 14 72 2e 11 39 0d 23 1b 37 00 28 14 3c 0a 26 1e 31 05 2d 13 3b 0f 20 18 34 02 2a 76 71 2d 13 77 40 68 54 0a 1e 31 4d 73 37 00 64 5c 06 61 59 03 2b 5f 04 32 36 01 29 15 3d 0b 27 1f 30 6c`

So, what could it be? I'm assuming that the display is showing something from either its internal memory or from the memory of its controller and that we are looking at consecutive memory locations (this could, also be incorrect).

Anyone else want to take a stab at this? Anyone know what company made the controller for the display or the lift?

The other thing that's odd is that there are lots of monotonic increasing sequences in the data. e.g. drop the ff and observe:
`c4 d8 ec00 14 28 4e 74 88 9c b0 c4 d8 ec 00 14 28 3c 50 64 78 8c a0 b4 c8 dc f0 04 18 2c 40 54 6e8e b4 c8 ee 02 16 2a 50 78 8c b2 ce ec 00 26 3a 60 86 9a c0 d4 fa 20 4c 6c 80 94 a8 bc d0 e4 f8 0c 36`

Nick Barnes said…
Take first differences.
Nick,

Brilliant! Why didn't I spot that?

Here are the first differences (mod 256):

255 197 20 20 20 20 20 38 38 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 26 32 38 20 38 20 20 20 38 40 20 38 28 30 20 38 20 38 38 20 38 20 38 38 44 32 20 20 20 20 20 20 20 20 42

And here are the numbers and their differences on two lines.

ff c4 d8 ec 00 14 28 4e 74 88 9c b0 c4 d8 ec 00 14 28 3c 50 64 78 8c a0 b4 c8 dc f0 04 18 2c 40 54 6e 8e b4 c8 ee 02 16 2a 50 78 8c b2 ce ec 00 26 3a 60 86 9a c0 d4 fa 20 4c 6c 80 94 a8 bc d0 e4 f8 0c 36
ff c5 14 14 14 14 14 26 26 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 1a 20 26 14 26 14 14 14 26 28 14 26 1c 1e 14 26 14 26 26 14 26 14 26 26 2c 20 14 14 14 14 14 14 14 14 2a

I wonder if it's possible to further dig into this and discover what causes that pattern?