A while ago I bought a Yaesu FT-2D in order to try some YSF with MMDVMs. I discovered that German shops sell the data cable for nearly 90€ which seems quite expensive - especially after discovering that I just contains a pl2303 USB-RS232 adapter and a MAX3232 or similar level coverter. So the only difficulty left to clone this cable was the connector on the radio side. There is a longer thread on Twitter about this (see [1]). Sources for the plug seem to be [2] and [3].
So I ordered a simple USB-RS232 converter with pl2303 chipset and also got hold of a sample connector that fits into the data jacket of the FT-2D. As the plug is made for PCB mount I designed a little PCB that I could solder the plug to. A little piece of wire and thats it for the home made data cable. The serial levels between the radio and the cable are RS-232 levels. That is why a MAX3232 or similar is needed.
This piece of wire can be used as outlined in the manuals. I was able to read and write my FT-2D as expected.
Please be aware that this may eventually break your rig. Use at your own risk. I am not liable in any way for damage to your equipment.
References
[1] https://twitter.com/travisgoodspeed/status/602492616685518849
[2] https://www3.panasonic.biz/ac/e/search_num/index.jsp?c=detail&part_no=AXJ443000
[3] http://www.suyin-europe.com/consumer-and-portable/