Hello Steve,
The '705JP7 dates from the early 1990s, and it was usual practice to purchase an "evaluation board" from Motorola that catered for program development. The board also provided for OTPROM programming. A single evaluation board would be applicable to only one or two device types with similar pin-outs.
For some of the devices, it was also possible to program them using a special hardware arrangement, in conjunction with an external EPROM that contained an image of the code. However, I have not been able to find the datasheet for the 'JP7 to see what was required for this device. To my knowledge, the programming algorithm was never publicly documented (although this was the pre-Internet period).
You may also find that some commercial PROM programmers of that vintage were also able to program a range of Motorola MCU devices.
Regards,
Mac