We are proposing a replacement controller for a customer. It uses a simple keyfob with a few buttons, like the ones to unlock your car. The customer would like to continue to use the same keyfob transmitter and the receiver in his device, but doesn't have a lot of details on it. [Hopefully, we'll get the info from him.]
I'd wager it is a "standard" protocol of some type, but I'm not conversant in this area. I'll bet one of you gurus can recognize it.
Anyway, here are a few pieces of info:
--Bit time appears to be 2ms. -- 500 bps.
--data stream repeats every 70ms. when a button held down
--data stream appears to be a 16 bit ID, and an 8 bit data byte indicating the button pressed
--the data stream has a high amplitude of about 3.7V. At the tail end of the 24 bit data stream, there are two pulses to 5V, 300us apart and 100us wide, that we assume are sync of some sort.
The edges are nice & clean & repeatable, so I don't anticipate many problems. But it would be helpful if someone could recognize the protocol so I could dig up references. TIA, & take care.