controlling ports on a network


Thread Starter


Hi folks,
I recently I developed an application for controlling a CCTV camera through an LPT port on a Server on an NT network. This is fairly straght forward as you only have to choose between two sets of ports;378 and 3f0. However, I now need to control this Camera connected to the Lpt port of the Server from one of the clients. Can any one tell me how to get the Hex address of this Network port?

Johan Bengtsson

Well, the answer to that one is easy: there isn't one. It does not work that way at all, the information sent over the network when you are using a printer on another computer don't have much in common with what is actually written to
the physical port, it is rather a list of graphics commands that is transferred and then converted by the printer-driver at the server.

The RAW transfer format is relatively close to what is written to the port, but there is no timing information and similar sent at all since it is the server doing that piece of the work.

The driver part at the client end doesn't even know if it is LPT, a serial or a network port or even a file the printout will appear on.

Sorry, can't be done in that way. You will have to write two pieces of the program, one to run on the server (where the camera is connected) and one to run on the client and use network commands to communicate between them. How that is done is a completely other chapter in programming knowlege.

Btw, the network card does of course have a hex adress, but don't even try to use that one directly - you would probably mess up a lot of things if you are not lucky enough to completely crash the OS before that happens....

/Johan Bengtsson

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Thanks a lot Mr.Bengtsson,
other people who were less knowledgeable on the hardware side have made the same suggestion. But yours comes with a stamp of authority. Guess I have to approach it the way you suggested.
The answer to your question is you can not connect to a hex address of a client on a remote next work. Although that does not mean to task you want to do is impossible. The are ways of
connecting to the clients machine using a like terminal application. I know on a windows 2000
network you can start the terminals service on the workstation and then you run a command line on
the remote pc. I don't know about windows nt.