I currently have a very fragile solution to connect my embedded device to a PC's serial port. This is mounted on the PCB: http://www.digikey.com/product-detail/en/DF13A-6P-1.25H(50)/H3384-ND/530681. Its companion must be painstakingly attached to the wires of an existing serial cable, and placing any sort of strain-relieving product takes too much expertise. The wires often break off. Only five pins of the six are used. I may be able to respin the board this connector must be on.
I'd like to replace it with a Micro-USB B receptacle so that I can cut open easily-obtainable Micro USB cables and mate them to a DB9 connector. Is the 5th pin actually wired on most cables? I don't know much about the USB standard. Does this seem like a decent idea?
EDIT: This port is factory accessible only.
Best Answer
The ominous Pin #5 is usually the ID Pin and does not travel through the cable. If I remember correctly, this pin is usually shorted to ground, indicating a device device or open, indicating a host device. In other words: This pin decides if the device which is connected plays the host or device role.
If you use the other 4 pins, make sure that no user will really use a "normal" USB cable (and they will) as your device will most likely get 5V on the power pin (which is probably not what you want).
PJCs solution is in my opinion a good one (but requires you to change the board)