Possible causes:
- Power Management is not disabled at BIOS setting.
RS-232C is activated by the power from DC-DC converter sourced at 5vdc for a Personal Computer.
Notebook PCs' default setting is to disable DC-DC converter in order to maximize the battery life.
When the COM port is used, the power management has to be disabled. - Power management at Windows control panel is not set therefore power is not always supplied.
- Set to use Active Desktop function.
Active desktop function uses overlay memory and therefore the CPU load is consumed. - Screen saver is being used.
RS232C operation may be delayed when screen saving starts. - Virus check software is running on the machine.
The latest virus check software always checks the data from the serial port. This may cause a timeout.
