vb.net telnet commands

[caffrey]

our new projector has a web interface as well as telnet (for some reason) I'm not sure if the web interface has an API

Anyway thought it would be nice of me, instead of using a remote - to develop a small application thatll turn the projector on and off.

I've wrote the program but it doesnt seem to work as intended (probably to do with my lack of coding fu) doesn't help the fact i've no idea what the program is doing when its running (would be handy to see a telnet window as its doing its stuff)

here's the code im trying to use well the sub that i pass a value to anyway

    Public Sub projectorcontrol(ByVal onoroff)

        Dim client As Net.Sockets.TcpClient
        Dim sr As IO.StreamReader
        Dim sw As IO.StreamWriter
        Dim ns As Net.Sockets.NetworkStream
        Dim response As String

        'connecting to a server
        client = New Net.Sockets.TcpClient
        Try
            client.Connect(projectorip, 10000) ' 10000 is the port number
        Catch e As Exception
            MessageBox.Show("Failed to connect: " & e.ToString, "Error")
            Return
        End Try

        ns = client.GetStream
        sr = New IO.StreamReader(ns, System.Text.Encoding.ASCII, True) ' this sends our commands to the server
        sw = New IO.StreamWriter(ns)  ' and this will read server's response

        sw.WriteLine("****" & ControlChars.CrLf) ' send pin number

        sw.Flush()

        sw.WriteLine(onoroff & ControlChars.CrLf) ' on or off is c00 on, c02 off

        response = sr.ReadLine()

    End Sub

The form is just two huge buttons saying ON OFF respectively

[peterp]

I seem to remember that the telnet protocol isn't as straight forward as just sending data over tcp.
You need to 1st send some configuration data (something about if you are accepting echo, and go ahead signals)
You have to send a 2 byte commands (255 <command>) the 255 states that the next byte is an instruction and not a character.

It's been a long time since I programmed a telnet client, but there should be plenty of info out on the googlesphere if you search telnet protocol.

Hope this points you in the right direction.
Pete.

[caffrey]

Thanks pete,

Been pretty much on hold as it's hard to test (i'm building then running to the hall to test, fails then repeat!) , some kind of output window would be beneficial then I can see if it's sending the right information.
Not a critical piece of code just one to help out

mark

[PiqueABoo]

Don't know if this Telnet class is any good (a glance suggests it will do), but I would find a free dotNet telnet class.


Failing that, I happily did cert authenticated SSH sessions to modify large amounts of config on some network gadgets a few years ago by simply calling the puTTY command line util from my dotNet code (puTTY does telnet too).

[caffrey]

cheers, i'll look into that too