If you have TCP-Com running as a server and are unable to connect a TCP/IP Client that is in the same network and subnet, then the first step is to double-check that the client’s configuration settings have the correct IP Address and TCP/IP Port number configured for the TCP-Com server. You should also check that the client is attempting to connect to the Server.
If the details are correct and the client is trying to connect, then the Windows Firewall or some other software or hardware Firewall could be blocking the incoming Client connection.* To allow the connections to get through, you will need to configure your Firewall settings.
Another possibility is that the Client is not in the same network or subnet as the workstation on which TCP-Com is running. For more information and possible solutions for this type of problem, please refer to Connecting to a Serial or Networked Device Over the Internet
*Normally, when you activate TCP-Com as a TCP/IP Server for the first time, the Windows Firewall will ask you whether you want to allow incoming Client connections to TCP-Com. If you select the option to enable connections, the Windows Firewall will create a rule allowing connections to TCP-Com from that point on.