I had a problem to connect SRX300 mini USB console port to the laptops (WIN7 & WIN10 both not working). Also,I had already installed the SRX300 usb serial console driver . When i plug in the mini USB cable to my laptop, the window does not pop up any USB detection and i cannot find any changes on device manager. (i am sure the USB port is working on the laptops).
On the other hand, somebody said it should configure the "system ports auxiliary port-type" to "mini-usb", but there is no port-type for SRX series. PLEASE HELP!!!
Looks like a hardware problem. I just tried on win10 x64 without any drivers. SRX300 console was immediately recognized as Juniper Networks BX Series System Console but with yellow exclamation mark. After installingdrivers from https://www.silabs.com/community/interface/knowledge-base.entry.html/2016/08/19/drivers_for_juniper-WkA6 COM port was assigned, and I was able to connect without any problems.
One thought... the USB -> mini USB cable; is that the one provided with the SRX300? The reason I'm asking is that a lot of other USB cables are only wired for power to charge devices. Do you have another device to test that all wires are present or use another cable?