Janus Sockets
Janus Sockets is a Sirius Software product that provides APIs for writing applications that use arbitrary protocols layered on top of the TCP/IP protocol. These APIs include low-level TCP/IP calls for communicating directly with the TCP/IP layer as well as higher-level APIs for using protocols such as HTTP (web requests) and SMTP (e-mail). The Janus Sockets product also provides an FTP Server that can be used without any User Language coding at all (though it can be extended with User Language code) and a telnet/tn3270 server that can be used to access Model 204 directly from a PC-based 3270 emulator.
See also the complete Sirius Software product list.