I used the 232 as the PC was introducing noise to the audio signal.
I used a phototransistor into a comparator then into a max202cpe (ttl to rs232 interface chip) then used a scope to get the timing right.
Replaced loader code with blinker code and edited to send start bit, data bits and stop bit.
Now I need to trim the dump as suggested by fe50 and find a disassembler (don't have IDA)
As the camera belongs to the wife, I'm just glad to no longer be upsetting her by "playing with the pretty lights" and running down the battery.