Private Function startListening(ByVal localPort As Long) As Boolean
    On Error GoTo errHandle

    If localPort > 0 Then
        'If the socket is already listening, and it's listening on the same port, don't bother restarting it.
        If (wckServer(0).State <> sckListening) Or (wckServer(0).localPort <> localPort) Then
            With wckServer(0)
                Call .Close
                .localPort = localPort
                Call .Listen
            End With
        End If

        'Return true, since the server is now listening for clients.
        startListening = True
   End If

   Exit Function
errHandle:
   startListening = False
End Function

Private Sub Form_Load()
    '1234 adalah port yg digunakan untuk komunikasi
    'antara server dan klien, nilainya bisa disesuaikan
    If startListening(1234) Then
        MsgBox "Status Server ON"
    Else
        MsgBox "Status Server OFF"
    End If
End Sub

Private Sub wckServer_Close(Index As Integer)
    ' Close the socket and raise the event to the parent.
    Call wckServer(Index).Close
End Sub

Private Sub wckServer_ConnectionRequest(Index As Integer, ByVal requestID As Long)
    Dim i          As Long
    Dim j          As Long
    Dim blnLoaded  As Boolean

    On Error GoTo errHandle

    ' We shouldn't get ConnectionRequests on any other socket than the listener
    ' (index 0), but check anyway. Also check that we're not going to exceed
    ' the MaxClients property.
    If (Index = 0) Then
        ' Check to see if we've got any sockets that are free.
        For i = 1 To wckServer.UBound
            If (wckServer(i).State = sckClosed) Then
                j = i
                Exit For
            End If
        Next i

        ' If we don't have any free sockets, load another on the array.
        If (j = 0) Then
            blnLoaded = True
            Call Load(wckServer(wckServer.UBound + 1))
            j = wckServer.Count - 1
        End If

        ' With the selected socket, reset it and accept the new connection.
        With wckServer(j)
            Call .Close
            Call .Accept(requestID)
        End With

    End If

    Exit Sub
    '
errHandle:
    ' Close the Winsock that caused the error.
    Call wckServer(0).Close
End Sub

Private Sub wckServer_DataArrival(Index As Integer, ByVal bytesTotal As Long)
    Dim cmd     As String

    On Error GoTo errHandle

    ' Grab the data from the specified Winsock object, and pass it to the parent.
    Call wckServer(Index).GetData(cmd)

    Select Case cmd
        Case "get_no_antrian"
            Call send(Index, CStr(noAntrian))

            lblNoAntrian.Caption = noAntrian
            noAntrian = noAntrian + 1 ' naikkan counter nomor antrian

        Case Else
            Call send(Index, "perintah tidak dikenal")
    End Select

    Exit Sub
errHandle:
   Call wckServer(Index).Close
End Sub

Private Sub send(ByVal lngIndex As Long, ByVal strData As String)
    If (wckServer(lngIndex).State = sckConnected) Then
        Call wckServer(lngIndex).SendData(strData): DoEvents
    Else
        Exit Sub
    End If
End Sub

Private Sub wckServer_Error(Index As Integer, ByVal Number As Integer, Description As String, ByVal Scode As Long, ByVal Source As String, ByVal HelpFile As String, ByVal HelpContext As Long, CancelDisplay As Boolean)
    Call wckServer(Index).Close
End Sub

Private Const conTunggu As Long = 100000

Private Function isConnected(ByVal ipServer As String, ByVal port As Long) As Boolean
    Static i As Long

    On Error Resume Next

    If myClient.State <> sckClosed Then myClient.Close ' close existing connection
    myClient.RemoteHost = ipServer
    myClient.RemotePort = port
    myClient.Connect

    With myClient
        Do Until .State = sckConnected
            DoEvents
            i = i + 1
            If i >= conTunggu Then
                i = 0
                Exit Function
            End If
        Loop
    End With

    isConnected = myClient.State = sckConnected
End Function

Private Sub cmdAmbilNoAntrian_Click()
    Dim ipServer    As String
    Dim cmd         As String

    ipServer = "127.0.0.1"
    cmd = "get_no_antrian"

    ' 1234 ada port yg menyesuaikan port yg ada di server
    If isConnected(ipServer, 1234) Then
        myClient.SendData cmd
    End If
End Sub

Private Sub myClient_DataArrival(ByVal bytesTotal As Long)
    Dim noAntrian As String

    On Error Resume Next

    myClient.GetData noAntrian
    lblNoAntrian.Caption = noAntrian
End Sub