6530 Programmer's Guide

Overview
6530 Programmer’s Guide 1-3
Modes of Operation The 6530 can operate in one of two major modes:
Conversational
Block
The mode selected determines how data is transmitted to the host, as well
as how certain control codes, escape sequences, and keyboard operations
function. You can select the mode best suited for your particular
application. You can also switch modes at different points in your
application.
Conversational mode
Conversational mode is useful for applications that need to interact with
the 6530 on a line-by-line basis, such as the host Tandem Advanced
Command Language (TACL). In this mode, the 6530 transmits data to the
host character by character as it is typed on the keyboard. The transfer is
terminated when the host receives a line termination character, such as a
carriage return (CR) character.
Half duplex
When the communications line is configured for half duplex, the 6530
processes characters entered from the keyboard as it transmits them to the
host. The 6530 interprets these characters as graphics (displayable)
characters or as control characters. Graphics characters are stored in
display memory and appear on the screen. Control characters are not
displayed or stored locally; instead, they cause the 6530 to perform
various functions. Characters received from the host are also interpreted
as graphics or control characters and are handled in the same way.
Full duplex
When the communications line is configured for full duplex, the 6530
only processes characters received from the host. Characters entered from
the keyboard are transmitted to the host, but they are not processed by the
6530 until they are echoed back by the host. Characters received from the
host are interpreted and processed in the same manner as in half duplex.
Chapter 2 describes the details of conversational mode operation.
Block mode
Block mode allows the application program to control the format of data
on the screen. In addition, the 6530 can perform more local processing
functions, such as editing tasks, and thus reduce host application
processing requirements.