Amazing post from Ketturi electronics designing a custom adapter for a 35-year-old retro computer:
Canon X-07 is great little handheld retro computer. But being Canon, nothin is standard. Canon has always insisted using weird proprietary connector for devices, and usually it is impossible to find connectors that would fit them. This is also a case with X-07. It uses weird connectors for serial- and parallel ports. They look bit like a normal D-sub connector, and D-sub connector almost fits into them, but it is not a good fit. I wanted to make new connector that matches X-07’s serial port perfectly, so I took my callipers and 3D cad and started to work.
Read more here.
I soldered cable on contacts. Printed partes were not installed during soldering, and white acrylic pin holder did not melt like printed parts would have been. I also installed small strain relief rubber jacket over cable. Other end is just terminated with normal pin-header style connector, so that I can plug it into USB -> TTL serial port adapter. X-07 uses ~5V logic in the serial port, and it cannot be connected to normal RS232 port without level converter circuitry. There is also 4.6V output from batteries in one pin, that could power level converter, IR transmitter or maybe even bluetooth serial adapter. Connector also has software switchable 38,4kHz signal for infrared transmission modulation.