My order got cancelled . Back-order it seems . These things seem to be getting rarer after 20 years .

If it costs more than 5USD then it is better to build yourself. The search engines are full of these http://pinouts.ru/Home/pc2midicable_pinout.shtml
It is very simple schematic. If you can even minimal way solder then You are able to build yourself. For this there are couple resistors, one opto isolator and 2 transistors.
CNY17- series optoisolator works too and other ones. Perhaps from a old broken impulse power supply optoisolator works too for this!!! So, all details are available in a local shop. Almost everything will work.
The opto isolator is a must be, otherwise it just does not work. Also, the cable grounding pin shall not be connected with synth. It shall be for cable shielding only!

The another version is if to replace 2 transistors with one logic IC chip LS7400, LS7404, LS7405, it is not so critical (can be also 74HC series and other ones which is available at the local shop),
Whatever if it is with logic chips or transistors, both versions tested and work EXACTLY the same way.

All these midi cables which have the shielding connected on both ends are incorrect.

I made all these adapters myself and it is simple as that.
ABout cable almost everything works if it is just a twisted pair or just ordinary stereo audio cable. I am using for cable also CAT5 becouse that one accomodates 4 pairs of this 😀 😉
So, switch on that soldering iron. Shall we? I could make some instructions if needed.

In the past I made those to my friends, and also all these are made for my synthesizers too. but I never bothered about idea to make them for sale since it is so simple to make like everyone could make them on every beautiful Wednesday.

If there's a Guitar Center or Sam Ash in your area it might be worth it to call them up to see if they still have one in stock. Might be able to get it at a deep discount just to get the thing out of their inventory.