X25AM Programming Manual

X25AM Programming Manual—527201-001
2-1
2 ITI Applications
This section describes how an application exchanges data with a remote terminal
connected to an X.25 packet-switching network with a packet assembler disassembler
(PAD). This requires X25AM and the Interactive Terminal Interface (ITI) protocol.
Topics covered in this section include:
ATP6100 I/Os Compared to X25AM
Accessing a remote terminal connected through an X.25 network to an X25AM I/O
process is very similar to accessing a remote terminal connected through a modem to
an ATP6100 I/O process. However, X25AM does not support every function provided
by ATP6100.
Applications written for either task are very similar. The information in this section is for
those aspects of application programming that pertain to X25AM and ITI. It provides a
description of the file-system interface to ITI, the exchange of data with the remote
terminal, and the programming tasks for an ITI application. In addition, a description of
the PAD and how it is controlled is included.
A discussion of the common aspects of programming an application that
communicates with a remote terminal is presented in the Guardian Programmer’s
Guide.
High-Level View of the Application and X25AM
Figure 2-1 on page 2-2 shows how the application and X25AM work together to
communicate between a NonStop system and a remote terminal through an X.25
packet-switched network.
Topic Page
ATP6100 I/Os Compared to X25AM
2-1
The ITI File-System Interface 2-2
Phases of a Connection 2-3
The PACKET ASSEMBLER/ DISASSEMBLER
(PAD)
2-7
Terminal Operation 2-13
Data Processing 2-16
ITI Application Programming 2-20
ITI Programming Example 2-45