HELP IN TURNING OFF ECHO IN SERIAL PORT

[babu]

HELLO ALL

I am new in serial port programming. I am currently doing a program
that communicates to DSP board through COM1 port. But I am using
Microsoft Visual Studio 2005. The language that I am using is C#. I am
using the built in class SerialPort provided by Microsoft. When I send
some bytes to the output buffer they always appear somewhat later at
the input buffer...
This is really frustrating.I know how to turn off the local echo in
the Hyperterminal, but there seems to be no method for doing this in
Microsoft Visual Studio.

Please help me to resolve this problem

Thanks in advance
Nasif

 

[Paul Burke]

When I send
some bytes to the output buffer they always appear somewhat later at
the input buffer...

Does the target board echo the characters?

 

[babu]

Does the target board echo the characters?

As far as I read about read about that board it does not echo

 

[Paul Burke]

As far as I read about read about that board it does not echo

Have you looked with a scope though? Don't spend time chasing a software
problem until you're sure the characters aren't physically present at
the input.

 

[Roger Hamlett]

HELLO ALL

I am new in serial port programming. I am currently doing a program
that communicates to DSP board through COM1 port. But I am using
Microsoft Visual Studio 2005. The language that I am using is C#. I am
using the built in class SerialPort provided by Microsoft. When I send
some bytes to the output buffer they always appear somewhat later at
the input buffer...
This is really frustrating.I know how to turn off the local echo in
the Hyperterminal, but there seems to be no method for doing this in
Microsoft Visual Studio.

Please help me to resolve this problem

Thanks in advance
Nasif

Are you sure it is the serial?.
If you are using a KeyPress event in a text box, to 'send' the serial
data, this event, must be set as 'handled', or the default behaviour will
be to type the character into the local text box, giving the same apparent
behaviour as local serial echo.
Just a thought.

Other thought. How are you sending the data to the DSP?. If you are using
a RS485 link, rather than RS232, these normally receive all data 'on' the
link, when it is sent. Hence the sending board, will see the transmitted
data, as well as any returned data.

Best Wishes

 

[The Real Andy]

HELLO ALL

I am new in serial port programming. I am currently doing a program
that communicates to DSP board through COM1 port. But I am using
Microsoft Visual Studio 2005. The language that I am using is C#. I am
using the built in class SerialPort provided by Microsoft. When I send
some bytes to the output buffer they always appear somewhat later at
the input buffer...
This is really frustrating.I know how to turn off the local echo in
the Hyperterminal, but there seems to be no method for doing this in
Microsoft Visual Studio.

Please help me to resolve this problem

Thanks in advance
Nasif

Depending on the hardware sometimes if you dont set
SerialPort.DtrEnable property to true it may echo, but this it rare
and is always immediate. I have also heard stories that using
WriteLine() with certain modem commands (not the commands that force
the modem to echo) can cause an echo. Failing that I would be looking
at the device you are communicating with.

 

[Si Ballenger]

As far as I read about read about that board it does not echo

Disconnect the device from your serial port and see if the echo
is still there.