Solved

Serial Port Drama

Posted on 2010-09-08
10
496 Views
Last Modified: 2013-12-17
Hi,

I am trying to do some simple comms via C# and a serial port however all is not quite working
as I expect.

I am trying to talk to my inbuilt modem and do a ATI4 <return> and I should get
back "HDA CX11270 Soft Modem" instead I get back the string I have
just sent.

I have included the code below.

Any ideas,

Thanks,

Ward.


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO.Ports;

namespace SerialTest1
{
    class Program
    {
        static void Main(string[] args)
        {

            SerialPort sp = new SerialPort();
            sp.BaudRate = 9600;
            sp.PortName = "COM3";
            sp.DataBits = 8;
            sp.StopBits = StopBits.One;
            sp.Parity = Parity.None;
            sp.Open();
            sp.WriteLine("ATI4\r");
            string received_data = sp.ReadLine();
            sp.Close();

            // I should get back:  HDA CX11270 Soft Modem
            // but instead I get back ATI4

            Console.WriteLine("Data: {0}", received_data);
        }
    }
}

Open in new window

0
Comment
Question by:whorsfall
  • 3
  • 3
  • 3
  • +1
10 Comments
 
LVL 10

Expert Comment

by:effx
ID: 33625853
Have you tride the same command using Hyper Terminal?
0
 

Author Comment

by:whorsfall
ID: 33625880
well i am using different terminal software but it does work.
0
 
LVL 10

Expert Comment

by:effx
ID: 33625934
Try:

string received_data = Console.ReadLine();

instead of:

string received_data = sp.ReadLine();

0
3 Use Cases for Connected Systems

Our Dev teams are like yours. They’re continually cranking out code for new features/bugs fixes, testing, deploying, testing some more, responding to production monitoring events and more. It’s complex. So, we thought you’d like to see what’s working for us.

 
LVL 10

Expert Comment

by:effx
ID: 33625995
Scrub my last try:

sp.WriteLine("ATI4\r\n");

Instead of:

sp.WriteLine("ATI4\r");
0
 

Author Comment

by:whorsfall
ID: 33626062
Hi,

Thanks for your response same result

Ward
0
 
LVL 3

Expert Comment

by:aledev
ID: 33626654
Try to put this line

sp.WriteLine("ATE0\r");

before this one

sp.WriteLine("ATI4\r");

and see what happens
0
 
LVL 3

Accepted Solution

by:
vusov earned 250 total points
ID: 33636281
Try to convert "ATI4" string to byte array and use sp.Write method
0
 
LVL 3

Expert Comment

by:aledev
ID: 33636501
If the echo of your modem is enabled, i think is normal that you read "ATI4" instead of  "HDA CX11270 Soft Modem" because the modem sends you back what you write (in this case "ATI4\r") so when you use ReadLine method it retrieves the first line in the buffer and probably the next one could be what you are looking for
Use this command for disable the echo and try again:

ATE0
0
 

Author Comment

by:whorsfall
ID: 33655650
Hi,

Ok I have made some changes and got it more succesfully working, maybee I could get an explination.

Here is the output.


Data:
HDA CX11270 Soft Modem
OK
 Length: 30


Code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO.Ports;

namespace SerialTest1
{
    class Program
    {
        static void Main(string[] args)
        {

            SerialPort sp = new SerialPort();
            sp.BaudRate = 9600;
            sp.PortName = "COM3";
            sp.DataBits = 8;
            sp.StopBits = StopBits.One;
            sp.Parity = Parity.None;
            sp.Open();
            sp.WriteLine("ATI4\r");

            int bytes = sp.BytesToRead;
            string received_data = sp.ReadExisting();
            int length = received_data.Length;
            sp.Close();

            // I should get back:  HDA CX11270 Soft Modem
            // but instead I get back ATI4

            Console.WriteLine("Data: {0} Length: {1}", received_data,length);

            //Console.ReadKey();
        }
    }
}

Open in new window

0
 
LVL 3

Assisted Solution

by:aledev
aledev earned 250 total points
ID: 33656358
when use ReadLine method look at the NewLine property and be sure that it is set to "\r" instead of "\n"
0

Featured Post

DevOps Toolchain Recommendations

Read this Gartner Research Note and discover how your IT organization can automate and optimize DevOps processes using a toolchain architecture.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Crystal reports vb.net 2 39
Best resource to learn entity framework 2 32
ASP.NET MVC 2 31
How come this regular expression allows "e"? 14 33
This article is for Object-Oriented Programming (OOP) beginners. An Interface contains declarations of events, indexers, methods and/or properties. Any class which implements the Interface should provide the concrete implementation for each Inter…
The article shows the basic steps of integrating an HTML theme template into an ASP.NET MVC project
Migrating to Microsoft Office 365 is becoming increasingly popular for organizations both large and small. If you have made the leap to Microsoft’s cloud platform, you know that you will need to create a corporate email signature for your Office 365…
Microsoft Active Directory, the widely used IT infrastructure, is known for its high risk of credential theft. The best way to test your Active Directory’s vulnerabilities to pass-the-ticket, pass-the-hash, privilege escalation, and malware attacks …

816 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

11 Experts available now in Live!

Get 1:1 Help Now