When you use TCP/IP communications, the following is also required:

TCP/IP must be installed and configured on the AS/400 system(s) concerned as well as on the corresponding network.
A TCP/IP protocol stack must be installed and configured on the PC system(s) concerned. The TCP/IP protocol stack must provide the Windows Sockets Application Programming Interface version 1.1 or higher. Any Winsock 1.1 (or higher) compliant TCP/IP implementation will suffice.
The TCP/IP protocol as included in Windows 2000 and up is compliant.
In some instances, you require a terminal emulator (5250 session) that supports PC Organiser (PCO). See the administration manual for more details.