> 3.2.2 | Turning the Module on and off

> In a Windows environment, the USB COM port emulation causes the USB port of the module to appear as a virtual COM port (VCOM port). The VCOM port emulation is only present when Windows can communicate with the module, and is lost when the module shuts down. Furthermore, the operating system maps the VCOM port number to an internal ID that changes each time the USB device is restarted, i.e. the VCOM port number is permanent, but the internal ID changes. Therefore, the host application or Terminal program must be disconnected from the USB VCOM port each time the module is restarted.
> Restart after shutdown with AT^SMSO:
> After entering the power down command AT^SMSO on one of the interfaces (ASC0, ASC1, USB) the PC application or Terminal program used on the USB VCOM port must be closed before the module can be restarted by activating the IGT line, or by replugging the USB cable between the module’s host application (e.g., the DSB75 Support Board) and the PC.
> Software reset with AT+CFUN=x,1:
> Likewise, when using the reset command AT+CFUN=x,1 ensure that the PC application or Terminal program on the USB VCOM port is closed down before the module restarts. The best approach is to quit this program first, and then enter the AT+CFUN=x,1 command from ASC0 or ASC1. Otherwise, if AT+CFUN=x,1 is entered on the USB interface then the PC application or Terminal program on the USB VCOM port must be closed down immediately after sending the command and receiving the OK response.
> Shutdown from Charge-only mode and restart:
> As specified in [1], the AT^SMSO command cannot be used to power down the module when in Charge-only mode. Instead, it is necessary to disconnect the charger.
> If the USB port is involved, the PC application or Terminal program connected to the VCOM port must be closed down before disconnecting the charger.