> 3.3 | Standby of the operating system

> If the operating system has been installed in ACPI mode, it supports improved power management by also sending computer components into suspend mode. The serial WinMux driver supports this power management by switching the module into standby mode, if the driver is in use by accessing one or more of the virtual ports. If the operating system has been properly configured together with the BIOS, incoming calls or real clock alarms wake the operating system up again. During this wake up the first characters sent by the module to the operating system via the serial interface are lost. This is no restriction of the serial WinMux driver, but caused by the operating system.
> E.g. in case of an incoming call the first RING event is lost. Usually this causes no problem because the RING is repeated every few seconds. However, in case of the real clock alarm the module only sends one CALA URC. As a result, the URC will not be indicated though the alarm will be correctly executed.
> Additionally, in some cases when the computer switches to suspend mode, this causes pulses on the serial interface signals which wake up the module again.