VB6 and VB.NET Serial (COM1) data error

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Hello,
I'm new to .NET. I have an application that is running in VB6. It sends text through COM1 port to another device.

When I converted the VB6 code to .NET the string it sends out is different! I have tried so many things and don't know what to do. I used a serial data analyzer and found the two strings are different even the the source code is the same.

VB6 source code:

VB

MSComm1.CommPort = 1
MSComm1.Settings = "9600,O,8,1"
MSComm1.PortOpen = True
MSComm1.Output = Chr(&H2B) & _
Chr(&H4) & _
Chr(&H3) & _
Chr(&HE8) & _
Chr(&H0) & _
Chr(&H2) & _
Chr(&HF6) & _
Chr(&H71)
MSComm1.PortOpen = False

The analyzer gets the following string in hex: 2B 04 03 E8 00 02 F6 71

VB.NET source code:

VB

Dim Port As SerialPort = New SerialPort("COM1", 9600, Parity.Odd, 8, StopBits.One)
Port.Open()
Port.Write(System.Convert.ToChar(&H2B) & _
System.Convert.ToChar(&H4) & _
System.Convert.ToChar(&H3) & _
System.Convert.ToChar(&HE8) & _
System.Convert.ToChar(&H0) & _
System.Convert.ToChar(&H2) & _
System.Convert.ToChar(&HF6) & _
System.Convert.ToChar(&H71))
Port.Close()

The analyzer gets the following string in hex: 2B 04 03 0F 00 02 3F 71

Why is there a difference in the string?
Please help me correct it...
Thanks

Posted 2-Feb-11 22:14pm

aattanayake

Updated 2-Feb-11 22:19pm

Prerak Patel

v2

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Comments

Sandeep Mewara 3-Feb-11 5:01am

Update from OP:
I found something interesting.

when I convert a number using System.Convert.ToChar(X) and sends it through serial the X can only be hex: 0 to hex:3F if I want to get the correct value from the other side. Any value greater than hex:3F will not be hex:3F.

for example if I send
hex:64 you will get hex:3F
send hex:E8 you will get hex:3F

It seems like it max out with a 6 bit register value,
Please help me correct this mess ...

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Richard MacCutchan · Answer 1 · 2011-02-02T22:27:00

Solution 1

I think the ToChar() conversion actually converts the 8 bit value to its Unicode equivalent thus creating a different value. Try using ToByte() instead.

Posted 2-Feb-11 22:27pm

Richard MacCutchan

Comments

Sandeep Mewara 3-Feb-11 5:00am

Comment from OP:
Dear Richard MacCutchan,
I think you are in the right track.

but this does not work:

Dim Port As SerialPort = New SerialPort("COM1", 9600, Parity.Odd, 8, StopBits.One)
Port.Open()
Port.Write(System.Convert.ToByte(&H2B) & _
System.Convert.ToByte(&H4) & _
System.Convert.ToByte(&H3) & _
System.Convert.ToByte(&HE8) & _
System.Convert.ToByte(&H0) & _
System.Convert.ToByte(&H2) & _
System.Convert.ToByte(&HF6) & _
System.Convert.ToByte(&H71))
Port.Close()