do the switches turn of all four/six conductors in the port or just the two power conductors ?

There is a switch behind each port to turn it on/off.

compatible with imac?

My 4 port mini USB hub is working fine connected to my PC. It does everything specified. I don't see why it wouldn't be compatible with an imac USB application.

How long is the cord?

Four inches from hub to USB connector.

Questions & Answers: Connectland USB 2.0 4-Port Mini Hub with On/Off Switch for Each-Port (CL-HUB20132)

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