My device has a USB B female connector on it. The hserout command goes to an FTDI (FT232) chip which then outputs over the USB connector. Normally my device functions as a client feeding information to a computer.

However, I would like to feed control information over to another device(audio file player) that normally functions as a client when connected to a computer. The audio player has a serial (db9) connector.

So what I tried to do initially was plug a standard USB cable into my device (using the USB B connector). Then I put a gender bender on the other end of the cable and plugged a USB to serial adapter into the gender bender and plugged the db9 into the audio player. This didn't work.

So the last thing I tried was to switch the D+, D- lines in the USB cable. And that didn't work either.

I just looked up the pinnout for the DB9 and I don't see a vcc pin like the usb. So I'm wondering if there is a problem with leaving the USB #1 and #4 pins connected the way they are. Unfortunately I don't even have a multimeter with me. I will try to get out and find one today and test this to make sure pin 5 on the db9 is to gnd.

let me know what you think.
Thank you,
Hylan