UPDATE:
check libraries for reading data from radio and writing to cluster:
https://github.com/tomaskovacik/VAGFISReader
https://github.com/tomaskovacik/VAGFISWriter
Here is wikipage with schematics:
https://github.com/tomaskovacik/VAGFISReader/wiki/How-to-connect
also page ti theory of operation:
https://github.com/tomaskovacik/VAGFISReader/wiki/Theory-of-operation
When writing to the cluster, no external components are required,the cluster has all these components inside.
I think, this apply for pre-CAN-BUS cars only, check sticker on your radio, if there are 3pins labled ENA DATA CLK in middle section of mini-iso connector:
some 2000 models can be switched from canbus to this 3lb protocol.
 
check libraries for reading data from radio and writing to cluster:
https://github.com/tomaskovacik/VAGFISReader
https://github.com/tomaskovacik/VAGFISWriter
Here is wikipage with schematics:
https://github.com/tomaskovacik/VAGFISReader/wiki/How-to-connect
also page ti theory of operation:
https://github.com/tomaskovacik/VAGFISReader/wiki/Theory-of-operation
When writing to the cluster, no external components are required,the cluster has all these components inside.
I think, this apply for pre-CAN-BUS cars only, check sticker on your radio, if there are 3pins labled ENA DATA CLK in middle section of mini-iso connector:
some 2000 models can be switched from canbus to this 3lb protocol.
|  | 
| static text | 
| DEC | 255-DEC | ASCII | REAL | ||||||||||
| 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 15 | 240 | ADDR? | |||
| 1 | 0 | 1 | 0 | 1 | 1 | 0 | 1 | 173 | 82 | R | |||
| 1 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 190 | 65 | A | |||
| 1 | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 187 | 68 | D | |||
| 1 | 0 | 1 | 1 | 0 | 1 | 1 | 0 | 182 | 73 | I | |||
| 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 176 | 79 | O | |||
| 1 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 153 | 102 | f | _ | ||
| 1 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 185 | 70 | F | |||
| 1 | 0 | 1 | 1 | 0 | 0 | 1 | 0 | 178 | 77 | M | |||
| 1 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 185 | 70 | F | |||
| 1 | 0 | 1 | 1 | 0 | 0 | 1 | 0 | 178 | 77 | M | |||
| 1 | 1 | 0 | 0 | 1 | 1 | 1 | 0 | 206 | 49 | 1 | |||
| 1 | 1 | 0 | 1 | 0 | 0 | 1 | 0 | 210 | 45 | - | |||
| 1 | 1 | 0 | 0 | 1 | 1 | 1 | 0 | 206 | 49 | 1 | |||
| 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 223 | 32 | ||||
| 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 223 | 32 | ||||
| 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 223 | 32 | ||||
| 1 | 1 | 0 | 1 | 1 | 0 | 1 | 0 | 218 | CRC | ||||
| 0 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 15 | 240 | ADDR? | |||
| 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 223 | 32 | ||||
| 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 223 | 32 | ||||
| 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 223 | 32 | ||||
| 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 199 | 56 | 8 | |||
| 1 | 1 | 0 | 0 | 0 | 1 | 1 | 0 | 198 | 57 | 9 | |||
| 1 | 1 | 0 | 1 | 0 | 0 | 0 | 1 | 209 | 46 | . | |||
| 1 | 1 | 0 | 0 | 1 | 1 | 0 | 0 | 204 | 51 | 3 | |||
| 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 223 | 32 | ||||
| 1 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 185 | 70 | F | |||
| 1 | 0 | 1 | 1 | 0 | 0 | 1 | 0 | 178 | 77 | M | |||
| 1 | 1 | 0 | 0 | 1 | 1 | 1 | 0 | 206 | 49 | 1 | |||
| 1 | 1 | 0 | 1 | 0 | 0 | 1 | 0 | 210 | 45 | - | |||
| 1 | 1 | 0 | 0 | 1 | 1 | 1 | 0 | 206 | 49 | 1 | |||
| 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 223 | 32 | ||||
| 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 223 | 32 | ||||
| 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 223 | 32 | ||||
| 1 | 1 | 0 | 0 | 0 | 1 | 0 | 0 | 196 | CRC | 
CRC=MODULO(SUM(255-DEC),256) = ((SUM(0xFF-HEX))&0xFF)
|  | 
| Starting "pulse" ? | 
|  | 
| packet | 
|  | 
| so, it's SPI!? | 
ENABLE is bi-direction "wire":
|  | |
| from audi concert plus | 
|  | 
| audi concert (nav)/chorus | 
Arduino code to receive from radio and to send text to cluster is down there:
Arduino code to send data from RS232 to cluster
Arduino code to receive data from radio
comunication betwen arduino reader and actual radio
video of code in action



 



















 
 







