Based in the internet research and my 4 cameras spanning 15 years, It appears the protocol is very stable as such commands such as record, power off focus, as such those command codes have not changed. But new commands such as mode or photo or more zoom speeds are added over the years. Given that there is room for 512 commands to the camera there should be enough space for awhile. Thus as sony new camera engineer uses the same codes as already in common use for common buttons there is compatablity. He is allowed to add new command to currently unused codes. Ive only seen only once electrical specification for it. And my great interest in what is in the 10pin, i dont have one to play with yet, assuming the same spec is presented as through the cable to the 2.5mm plug. There are 3 wires, ground , power, and the lanc signal. The signal is bidirectional on one wire. Avhieved using timing pulses from the camera, the remote must get in sync with the timing and then send a two byte command while in camera exact bit sync. So a laundry listis , the cable failed to pass the power (if remote is not self powered), failed to pass the lanc, the camera is not sending the those, or the bit 0 signal level is just too different . A quick check is to use a 2.5mm cable break out and put a scope on it. One weired example i saw on the first generation topdawg is that when the hc9 was plugged in, the housing sent utter gargage codes for focus , yet good codes for power off, record, zoom,, and focus for earier cameras, this suggested some sort of discision choice in the housing based on camera lanc data but camera (too new for a lookup table?). Certainly not really nessary since the focus command hasnt changed in cameras ive seen.