gtps2m4aACF/SNA Data Communications Reference

Appendix F. TPF Message Processing Flow User Extensions

This section details how you can extend TPF terminal support. The key feature of this extended support are user-written programs that transform the protocol used by the terminal into the standard TPF Application Program Interface. This extended support may be performed as part of your normal application process or as a separate application front ending your normal application process. Similarly, although it may also be used for other SNA protocols, this discussion focuses on using the PSV exits to implement a Communication and Transmission Control Program (CTCP) for the NPSI Generalized Access to X.25 Terminal Extension (GATE) environment. See Process Selection Vector (PSV) for detailed information on PSVs.