Thanks for some clarification on your question.
What it sounds like is the following:
1) You're creating a functionality that will locate vehicles through some third-party device. You can query this via serial port and it will return GPS co-ordinates.
2) You're also creating a web front-end that can view the co-ordinates of the vehicles.
Here's my recommendation:
1) Separate the apps. You'll have a better experience if you poll the device periodically (say once a minute) in a service application and store the results in a DB/memory. Think about this from a user perspective: if you intend to grow at all, and 10 people hit the page at once and you're doing on-demand loading, you'll run into all kinds of problems with data access. Your serial port will become a bottleneck very quickly.
2) In your web app, use jQuery (or another JS library) to load your co-ordinates in time with the server polling from #1. You're only reading from the DB in this case; very easy.
3) Make sure you understand your licencing in the mapping applications. You can't use Bing Maps or Google Maps for free if you don't provide free access to your maps.
As far as connecting to the device, try contacting the manufacturer. They will have a list of commands, or an SDK that you can use to communicate with the device. As well, the
MSDN[
^] docs on SerialPort are actually pretty good and will point you in the right direction. If you have specific questions, please do not hesitate to ask.
Cheers.
Submit an article or tip