Is there a “compatibility” mode for the remote control binary packet protocol that looks like that in the PSM-2100?
No. The new commands dictated a new structure to implement the significantly greater number of commands available in the PSM-500/4900. Many items such as the interface structure, data rates and available options are so different that creating a compatible command set was impossible. The packet structure itself is virtually identical though and in most cases the new command set can be accommodated by a “driver” tailored to the PSM-500/4900.