How to connect two ethernet cable in parallel?

[Bharathi1]

Hi,

I am interfacing PC with LED Display module using ethernet cable, I have a software in my PC to upload image to the module, now i want to see the data packets when my PC sends data to the led module, i thought of interfacing intermediate PC between my PC and LED display module, but i am not getting how to see the data?, Is it good method to connect ethernet cable in parallel?, Is there any data loss?:-(

 

[BradtheRad]

Yes, it helps to put in a middleman device. The computers themselves do not always alert us to a lapse in communication.

To have a simple indicator showing whether packets are going back and forth, you might try an ethernet hub. (Or possibly a an ethernet switch, or router, because the functions are not always distinct.)

I have an ethernet switch. It is a useful diagnostic tool. It has led's at each outlet. They indicate communication between computers, or when there is not.

They flash on and off rapidly during a long download. Or, sometimes they flash for a second or two, then go off. This alerts me that communication was opened, but then stopped for some reason. Example, when one computer does not recognize the other.

 

[FvM]

I presume, "ethernet cable" actually means an ethernet link, e.g. 10 or 100 Mbit/s, not a different interface using a RJ45 cable?

The easiest way to intercept the ethernet communication between a PC and a peer is to run Wireshark on the PC.

If this is not possible for any reason, you can connect an intelligent ethernet switch with forwarding capability or an old style ethernet hub between both devices to send a copy of all data packets to another PC running Wireshark.