SNAX/APN Application Programming Manual

SNAX/APN Application Programming Manual—420111-001
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Introduction to SNAX/APN
High-Level APIs
This section provides an introduction to the SNAX/APN high-level application program
interfaces, CRT and ITI. For the low-level, SNALU interface, see Section 4, The
SNALU Interface.
This section is divided into the following subsections:
•
The CRT and ITI Interfaces
•
Configuration Requirements for CRT and ITI
•
LU-LU Sessions Between Applications and Devices
The CRT and ITI Interfaces
SNAX/APN provides support for two high-level APIs: the CRT interface and the
interactive terminal interface (ITI). These interfaces simplify communication between
an application process running on a Tandem NonStop system and SNA 3270-type
devices on a separate IBM subarea network. You select the appropriate interface by
specifying which high-level protocol you want to use:
•
The CRT protocol supports block-mode (or page-mode) communication for use with
display terminals and printers. The CRT protocol is described in Section 2, The
CRT Interface.
•
The ITI (interactive terminal interface) protocol supports conversational-mode (or
line-at-a-time) communication with display terminals. The ITI protocol is described
in Section 3, The ITI Interface.