How to make a TCP connection between ROS PC and a custom robot controller（TMS320C6748）? [closed]

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Hi. I am a beginner in ROS /ROS-I. I have asked the same question on mailing List but no one give me suggestions.I am so sorry that ask the same question here again. Now my lab want to develop a new control system using ROS-I. The hardware has completed and what I need to do is building the software part.I have read the tutorial of ROS-I and most of the wiki introduction of ROS-I and have a general understand. When I decided to start the work I still have many confusion and need some help and support. Here are my questions.I will be appreciate if anyone can give me some suggestion. To build the whole control system the first part I need to do is build the connection between ROS PC and the Robot Controller. the Robot Controller we used is developed from a DSP (TMS320C6748)made by TI,which support C/C++.Now I have some questions .

1.I learned that interface layer which actually is a client.but I don't know how the client combine itself with simple message or use simple message?

2.Simple_message defines a simple messaging connection and protocol for communicating with an industrial robot controller.is there any node in simple message?I didn't found it.

3.I want to build the TCP connection via Ethernet . And I learned that I should build a server on the robot controller.Is there any example about the server?I didn't find any example or documents about that.
4. When data send to the robot controller by using simple message, how is the data decoded on the robot controller? In the description of simple_message package, The typed message base class provides methods for creating topic, reply, and request messages. If used in both the client and server, the developer need not understand the structure of the data payload. I guess that I should put the simple message on the robot controller,right?But how to use it?

5.In the industrial_robot_client, there are two different way to send data,JointTrajectoryDownloader and JointTrajectoryStreamer. From their description I think the downloader one will be a good choice because it download all the point information to robot controller at once ,however steamer need many times.But there is no example how to use this method. If I use steamer , I want to send the point position at least 125HZ. How can I do this successfully? 6. I'm a beginner,so I don't know How to start the project.Should I understand the whole code in industrial_core?Or just know how to use it? I still have many questions about this project,so it is extremely hard for me to complete the project. I will be appreciate if someone can give me some suggestions.Thanks!