USB A to B connectors back to back
USB isolation is good for you. Isolated DAC makes better sound, isolated oscilloscope produces cleaner trace, and making line voltage measurements with isolated instruments helps us live longer. However, USB isolation often comes with a cost of extra USB cable, which may become excessive if we take into account precious desk space taken by said cable, as well as time spent on finding and untangling it.
I made several attempts to build a short cable which would also be able to bear load of USB isolator. Finally, while searching for a source of PCB mounted USB male B-type connector, I found this little marvel on eBay.
There is not much to say about it. It is short rigid adapter with USB A-type connector on one end and B-type on the other. The following picture shows typical arrangement – USB isolator connected to my Bitscope with USB adapter holding isolator in the air.
Of course, this little adapter can be used for connecting many other devices. Another picture shows our beloved Arduino connected to a USB port of a laptop computer. Here the weak spot of the adapter is clearly seen – since A and B connectors are turned 180 degrees, connected device would be turned upside down. For isolator it doesn’t matter much; however, operating Arduino’s Reset button and connecting shields would be difficult.
Adapter is available from several sources on eBay. Prices vary from $0.90 to $2.00, often with free shipping. The search string is “USB 2.0 Male to Printer Scanner A-B Converter Adapter”. Enjoy!
Oleg.
 USB Isolator connected to Bitscope using short cable |
 Using USB adapter to connect Arduino to a PC |
Is that a Bitscope BS310U I see? 😉
That’s correct – one of my favorite instruments :-). Its inputs are very sensitive so USB ground noise is a big issue. That’s probably why they started making scopes with USB isolation right after this model.
These can be found pretty readily online by searching for “USB gender changer”.