ITU-T X.25 Protocol Module (with RFC1613 XOT) - C Source Library (supplied with full source code) implements ITU-T recommendation X.25 - Interface between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE) for terminals operating in the packet mode. HS X.25 includes HsDL (Data Link with RFC1613 Cisco Mode XOT) and HsSock (Winsock interface) for X.25 over TCP applications