WP7611 - Yellow Brd Enable/Disable USB to reach low power state

WP7611+Yellow EVB is connected to ATT cellular network. MIMO 2x2 config. The Yellow EVB is connected to Windows PC via USB cable
We had to use a dialup connection (dial *99#) to get internet using the cellular modem.
Can you please tell me how to enable and disable USB in this configuration to attain the lowest connected power mode -2mA.
Do we use UART1 interface for AT command based Modem status monitoring when the USB interface is disabled ?

You can remove the USB cable from the host or you need to set the USB to selective suspend mode so that it will ask the module to go to sleep mode when not using.

in linux, we set it the the value of /sys/bus/usb/devices/5-1/power/level to “auto”.

From waking the module by UART1, you need to see AT+KSLEEP command.