i need only to get any voltage out from my laptop to control a relay
how to get a signal from a LAN port from any pin ?
in my laptop there is no com Port or lpt Port
also the usb port needs interfacing circuits which is not nessesary
in my simple project
thats why i choosed the LAN Port
i use (visual basic 6)
any help would much appriciated .
While such things as PoE exist, normal ports do not provide any power to external devices. The USB ports are far more likely candidates since they are designed to support powering external devices, though the amount of current supported varies by adapter/hub (most "ports" are actually internal hub ports).
Related
First allow me to say that I don't have any experience developing drivers for OSX, nor drivers for Windows. So, there are a lot of things that I don't understand about how drivers work; I'm sure it'll be evident in my question.
I have a modem that is able to open and close TCP/UDP sockets using AT commands. I would like to create some kind of program (kernel extension? driver?) that implements a network driver, converting the network interface calls into AT command serial messages.
That's the basic jist of it. I'm essentially asking if anybody can point me in the right direction / give me a high level overview of how they would approach it and what Apple guides to focus on.
The XNU networking stack -- like most network stacks -- expects network devices to send and receive IP packets directly. It isn't tooled to work with network devices that handle part of the network stack (like TCP or UDP) internally -- it won't be possible to implement a network driver which uses this device.
You might have more luck exposing this device as a SOCKS proxy. You will need to write a userspace daemon which listens on a TCP port on localhost (on the computer) and relays traffic to the serial device; once that's done, you can set the computer to use that device as a SOCKS proxy in the Networking control panel.
(As an aside: most devices that implement this type of interface have a very low limit on the number of open sockets -- often fewer than 10. They're unlikely to be able to handle the network load generated by a desktop OS.)
I have to base a critical Windows 7 software on virtual COM Port assignment. The software has to test devices in a production line. Each device is different and needs to be supplied with individual security keys.
There are 20 serial connections from an USB-Serial bridge (Silicon Lab CP2103). Each connection on a physical USB Port gets some virtual COM Port, which I can adapt by the device manager (e.g. to COM7).
If the serial number of the bridges are all the same, I was told, that Windows remembers the chosen COM Port for each USB Port. Can I rely on that to be "stable" under restarts and other USB activities, not related to my adapters?
What would be the difference, if each adapter has individual serial number: Is it true, that in this case Windows remembers the COM assignment, but is doesn't matter which physical USB port is used for connection?
Are there any recommendations to do it in one or an another way?
I have a created hardware communicating application using RS232 protocol in MFC. But as there is problem regarding voltage signal strength, i would like to shift from RS232 to TCP/IP.
Can anyone help me on this topic...?
The solution is to extend the microcontroller board with a serial device server.
Known brands are Lantronix or Moxa, but there are many other options and manufacturers. For an "embedded" solution that is integrated on your board, the "Lantronix XPort" is a typical product.
http://www.lantronix.com/device-networking/embedded-device-servers/xport.html
(I'm not affiliated with the Lantronix company.)
The Serial Device Server will connect to your RS232 on one end, and on its TCP/Ethernet side it offers usually a TCP server. It is usually configurable via network, through a built-in web interface, much like an Internet router.
Your PC application then needs to be changed as follows: Instead of opening a Windows COM port, you need to make a TCP client connection to that server, on a preconfigured TCP port. (Lantronix has 10001 as the default TCP port for this.)
But there is also special Windows driver software that lets you talk to your Serial Device Server / your microcontroller through a "virtual COM port". This is sometimes the best solution for legacy PC applications, where you cannot change the original code and have to use a Windows COM port. For a MFC application this might be a good choice.
Preliminary story
There is this program which uses the Parallel Port to synchronize with other hardware. It will set the Parallel Port output to a specified (byte) value. This works without problems when using the built-in Parallel Port of a PC. The target platforms are Windows XP to 7, all worked fine so far. Source code is in Delphi, accessible and can be modified.
How it works
In Delphi I can use the io.dll to set the value of the Parallel Port, but there are also other solutions available, like inpout32.dll or port.dll. I call something like PortOut, specify a port number and the byte value and the port is set.
What I now want to do - and where I need help
Now the change: this needs to work on a machine which has no Parallel Port built-in (not even on the mainboard). There are several options available:
use a USB to Parallel Port adapter to add a LPT port to the PC
use a PCI card which adds a LPT port to the PC
use a PCI Express card which adds a LPT port to the PC
I am currently heading for and concentrating on the easiest and cheapest possibility: a USB to Parallel Port adapter.
Main question
There seem to be differences between Parallel Port adapters which are made to connect just a printer and other adapters which seem to be more powerful. Is there really a difference? Or can I just use one of these 5$ printer-adapters, plug in my own hardware and access the port from Delphi code? Or do I need a special adapter? Has anyone experience with this? There is a related question here, but the different adapter types (if existent) are not mentioned there. This page suggests that there are indeed differences:
Contrary to all other USB parallel ports which can connect to printers only, this makes connection to most hardware.
I hope there exists a solution via USB because for this you don't have to open the PC, which means the adapter can be added on demand.
Sub-question
Do you have experience with PCI (Express) solution? I have to use one if the USB approach is not successful.
Since I've been wrestling with this very thing recently here's what I've discovered; If you mean by using IO port addressing (indicated by your reference to inpout32.dll), no. Unless your USB-parallel port driver supports full port emulation or virtualization, which most do not, this is generally not possible. If you need to directly access the port to do normal "bit-twiddling", you should get a separate Parallel port PCI-card. Most of them present themselves as normal IO at the standard address(es). I am presuming you're not planning on using the parallel port to actually communicate with a printer, right?
What is interesting is that USB-Serial adapters are much easier to use since they appear as simple virtual devices where you can merely "open" them using a simple stream; TFileStream.Create("COM1", fmOpenRead) or Windows.CreateFile("COM2", ...);
Here is some devices that purport to do full emulation of a parallel port through USB:
https://www-user.tu-chemnitz.de/~ygu/bastelecke/PC/USB2LPT/index.en.htm
I'm working on an App that talks to a serial port, and on my development machine, I'm running Vista, and that serial port is a Bluetooth connection. Occasionally, the serial port gets caught in a state where my App can no longer connect to it. In .net I get an IOException with a message reading "Element not found."
I've tried restarting the App, connecting with other Apps (a communications client like HyperTerm) but nothing helps. I can't find any more specific error message, and nothing is logged to the machine's event logs. The device manager tells me the port is "working properly."
Is there any way to find out which process and or .dll has possession of a serial port, and/or force a port closed?
If it makes any difference, my App is in C#, but structurally, it's not convenient to open and close the port with a "using" statement.
Thanks,
Andy
To the best of my knowledge you can't close a serial port that you do not have the handle to. My experience of Bluetooth serial ports is that they can end up getting mapped to different COM port numbers at connection time, and can sometimes leave bogus COM ports when disconnected. For example, I currently have no bluetooth devices connected, but if I go into device manager, I see a total of eleven COM ports listed as Bluetooth serial port The properties on each of these ports show the device as working and available, and I can usually open these ports though I get occasional failures. My work around for this is to force COM port numbers for connected deviced, through properties / advanced / COM port number. I'm not sure if the problem is driver related (IVT corp in this case) or a problem with the way Windows manages blutooth serial ports.
Sorry I couldn't be of any more help.