In previous post I published MC75's connector pinout.
I have RS232 Cable (25-102776-02R). I must say that there is an inconvenience - this is "client" cable with DB9-F connector. If I want to use MC75 as host for some other device, for example, some microcontroller-based device, I must use an adapter.
Same can be said about
USB/Client Communication Cable 25-68596-01R. It has USB-A jack connector which makes the same inconvenience - a need to use an adapter. In addition I must mention that cable is big and expensive.
All this mixed in my brain and led me to an idea.
I searched internet and found MCNK-721001M connector of some company in China. This connector is available in Russia. It shouldn't cost more than $2. As it can be seen from it's part number - it is intended for Nokia 7210. This connector has almost same guide/fixing pins as MC75 connector. But total number of pins in MCNK is less and grid spacing is slightly different.
But it is not a great problem as long as we need only 4 pins for USB communication and pins #1 and #16 for charging.
First - remove two metal springs from connector. We do not need them anymore.
Then remove plastic clip from genuine MC75 cable. It is better to use it because it provides an ideal placing and fixing of cable connector in front of device connector. From the other hand - genuine cable is expensive, so you can try to make some replacement.
Now we must make some "frame" to attach our handmade connector to genuine clip. I made this frame from thin sheet of steel using file and industrial grade Dremel-like power tool with cutting disc. Then I soldered two nuts which will provide attaching frame to clip with common screws.
Then I slightly sawed guide pins of the MCNK connector making them fit into MC75 connector.
I also sawed off one pin at the side if MCNK because it is useless.
I marked 4 USB pins and slightly bend them to the centre of this 4-pin group.
Then I put connector into frame. You should pay great attention to positioning it! Especially depth. To fast fix connector in frame you may flatten the frame by hammering it's edge.
After that I tried to mate my handmade connector with MC75. After some little trimming all fitted and I glued connector to frame with two component epoxy. I used Poxipol - I like its greyish colour and it is well adhesive to metal and plastic. After epoxy completely harden you may need to remove some of it.
Then I took female USB connector from cable. The benefit was that cable had connector with connector cover and cover was detachable.
Using coloured wires I coccected MCNK and USB. Also I connected wires for charge - with bigger diameter and +5V brown to exclude confusion with +5V from USB.
Adjust wire length and solder USB connector. Adjust epoxy for USB cover.
Finally - do final check whether all connections made properly, close USB cover.
Made some "mould" of paper and pour it with epoxy. Better to use syringe - it allows to fill all small cavities.
It may require several stages to pour all desirable space.
For charging I used the same connector which is used in genuine cable - DS-212. Adjust wire length. If necessary - make some space by removing excess epoxy. Solder connector to wires.
I used little piece of wood to secure DS-212 connector by insulation tape. I just taped it to USB connector and put wood in between. Then pour the rest of space with epoxy.
Saw excess epoxy until it fits into plastic clip and other part will be nice to your eye. Screw up screws.
Now you may need slightly bend USB pins to provide good connection. Charge pins most likely do not need any trimming.
Job finished! Now you can charge and/or use standard keyboard, mouse, flash drive, etc.
