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New Data Error Handling option defines what to do in case of data
transmission errors- discard the data automatically or prompt the user.
The Problem Do you know what will happen if your program opens the serial port of the PC,
sends some data and then the PC cannot output this data through the serial
port (such situation is possible when, for example, the serial device
attached to your PC's serial port is unable to receive the data and keeps
its RTS output in "disabled" state)? Surprising (for many of
you) answer is...
The PC will freeze! Unfortunately,
the serial port services in Windows do not utilize the multitasking
capabilities of the operating system. After your program outputs the data
to the serial port your PC can do nothing until the all data is sent out.
You cannot even close your program at that time! Visually this appears as
if your PC has hanged up. In fact, the PC is just waiting for the data to
get through.
When
you deal with a regular serial port such situation won't happen very
often. After all, most serial devices can normally accept the data without
a long delay. With the Virtual Serial Port (VSP) the situation is
different. The VSP communicates with the DS100 (EM100) which is located on
the TCP/IP network and there are many things that can go wrong on a
network! If the DS100 (EM100) cannot be reached for some reason (because
it is offline, because the network is down, etc.) and your software
outputs the data to the VSP then the VSP will be unable to send the data
and your PC will appear to be hanged up! This is because VSP emulates the
standard behavior of the serial port... and this, unfortunately, means
that it inherits all the problems of the standard serial port
too!
The Solution To
free you from having to reboot your PC each time the VSP cannot transmit
the data to the DS100 (EM100) we have modified the behavior of the VSP to
incorporate the data transmission timeout. If the VSP is unable to send
the data to the DS100 (EM100) for a 5 seconds then one of the following
happens:
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