Hi there,
I just found this thread and wondered whether somebody is still interested in this issue...
Even though I'm nowhere close to actually understanding the protocol used by the Lamp Driver
(mine seems to be made by Ushio Japan / Phihong), I managed to crudely decode the packages
sent and received by either side. Punching these found bits into a very improvised program
left me with my projector up and running though(without ballast of course).
If anyone is interested in the data, I am willing to share/investigate further.
Projector: NEC VT48
Bought off Ebay for a couple of bucks, Lamp smashed to bits/exploded.
Lamp Ballast: PHG201G21 150W Ushio Inc. 250-420V= in, Four wire out(Lamp + separate Ignition), 5 Wire interface PWB002A
Hooked up a Halide lamp and took my scope out; results => see attachment.
Your findings might deviate, my lamp settings seem to be Eco => decreased Power consumption.
Obviously there's all sorts of issues to be resolved e.g. right now theres no acknowledged lamp shutoff
when i turn off the projector, causing it to beep and do a 1min cooldown run on next startup etc.
So much for now, i hope this helps

Regards,
Robert
EDIT: Two identical attachments, removed one
EDIT2: Micro used is Attiny 25 with Atmelstudio and AVR Dragon.
Since Neckro replied via PM I'll look for compliance to the Osram UART...