Receive garbage data from bluetooth which receive data from serail device

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  • sankothari2002
    New Member
    • Jan 2010
    • 1

    Receive garbage data from bluetooth which receive data from serail device

    Recently we have connected one bluetooth device which receive data from our serial device. The bluetooth device further transmite this data to a Windows Mobile which is bluetooth enable. Baud rate of whole system is 19200 with 7 data bit and 1 stop bit and Even Parity.When we send command to serial device through bluetooth device it is accepting the command and respond accordingly. but some of data byte of string is desplay as question mark (?).

    But in case we connect the serial device directly to PC, the string received is correct.

    Code of vb.net program which I run in windows mobile is below:
    Imports System
    Imports System.IO.Ports
    Imports System.Windows. Forms.TextBox
    Public Class frmSelectComPor t

    Dim WithEvent port1 as serialport = _
    New SerialPort(“Com 2”,19200,Parity .Even, 7, StopBits.One)

    Private Sub MnuConnect_Clic k(ByVal sender As System.Object, ByVal e As System.EventArg s) Handles MnuConnect.Clic k

    If port1.IsOpen Then
    port1.Close()
    End If
    port1.DtrEnable = True
    port1.RtsEnable = True
    port1.ReceivedB ytesThreshold = 1
    port1.Open()

    Dim str1,strcmd,str ReadSegment0 As String
    Str1="09RD00000 1"
    strchksum=23
    strcmd = New String(Chr(2) + str1 + Chr(3) + strchksum) + Chr(0)
    Delay(5000)
    port1.Write(str cmd, 0, strcmd.Length)
    System.Threadin g.Thread.Sleep( 70)
    Delay(2000)
    strReadSegment0 = port1.ReadExist ing
    ‘here I receive the following string "?09?D03?A D?

    End Sub


    Private Sub Delay(ByVal num As Double)
    Dim i As Double
    For i = 0 To num
    Next
    End Sub
    End Class
    Command Given to Serial Port is "09RD000001 23
    Response given by Serial Port is "?09?D03?A D?
    But I Expect the following input from serial port : "09RD033A DA

    Kindly provide the solution ASAP
  • RedSon
    Recognized Expert Expert
    • Jan 2007
    • 4980

    #2
    I would say it's a radio interference error. Is there some kind of checksum that you can use in the packet? Try looping your program to try again until there are no more unknown characters, maybe it will correct itself?

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