micky wrote:
I have a Y-shaped USB cable, 18" long, with type A at one end and the
two previously most common mini's at the other end, the one that used to
be used for cell phones and the other slightly bigger one.

All 3 ends have the USB logo in the plastic.

Doesn't that mean it's both power and data?

If it were power only, it should not have the logo, right?

Yet when I plug one end into the computer and another end into a Harmony
remote control, I get no beeps from the computer. So that means the
cable is defective, right?


I've had it for years, but I guess I've never used it except for
charging things.

It sounds like a hydra cable. The end with the two Host-side connectors, is this:

VCC
-
-
GND

VCC
D+
D-
GND

This means the peripheral *absolutely needs* the lower one
to be connected to the Host, as there'd be no data path without it.

The top one is a DC power path from a second USB Host jack to try
to get enough power. It has no data wires.

Hydra cables are used with 2.5" portable hard drives, to get
enough current to meet the "5V @ 1A for 10 seconds" spinup
current requirement. Once the drive is up to speed,
the motor current flow is reduced.

Paul