Controllers And Terminals; Programming Support - IBM 3174 Introduction Manual

Tables of the features, functions, and devices supported by the 3174 are shown in
Appendix A, "Quick-Reference Tables." Many of these features and functions are
discussed in other parts of the book, but these tables provide a quick-reference
point.
Controllers and Terminals
When attached to a controller, display stations, workstations, printers, and
personal computers are referred to as terminals. The 3174 controller can attach up
to thirty-two 3270 terminals and 24 ASCII terminals or hosts directly or up to 250
terminals in a Token-Ring environment.
The controller and its attached terminals are called a cluster. Controllers are
grouped into three cluster types, based on the number of devices they support.
IBM 3174 Controller Models 1L, 11L, 1R, 11R, 2R, 12R, 3R, and 13R are
large-cluster controllers. They have a four-port terminal adapter for attaching
terminals either directly (four terminals) or using one to four optional Terminal
Multiplexer Adapter features (up to 32 terminals). Terminals can also be attached
using 3299 Terminal Multiplexers and/or Asynchronous Emulation Adapters (AEA).
A multiplexer offers the advantage of connecting eight terminals to one 3174 port.
Less cable is needed when the multiplexer is located close to the cluster of eight
terminals. An AEA connects eight ASCII terminals or hosts to one 3174 port, and
up to three adapter features can be installed in the 3174 (24 ASCII terminals).
Medium-cluster Models 51 R, 61 R, 52R, 62R, 53R, and 63R have a similar
attachment flexibility, but with a maximum of 16 terminals (and eight ASCII
terminals). A base unit has a nine-port terminal adapter for attaching terminals
either directly (nine terminals), through two 3299 Terminal Multiplexers (Sixteen
terminals), or a combination of one 3299 (eight terminals) and eight terminals
directly attached (for a total of sixteen 3270 terminals) and eight ASCII terminals.
Models 81 R, 91 R, 82R, and 92R are small-cluster controllers. They have a four-port
terminal adapter for attaching terminals directly or through a 3299 Terminal
Multiplexer. Four terminals can be attached directly, or eight terminals maximum
can be attached using a 3299 multiplexer.
Controllers also can be grouped according to their attachment type:
• Locally attached models:
- 3174 Models 1L and 11L -large cluster
• Remotely attached models:
Programming Support
Models 1 R, 11 R, 2R, 12R, 3R, and 13R -large cluster
Models 51 R, 61 R, 52R, 62R, 53R, and 63R - medium cluster
Models 81R, 91R, 82R, and 92R - small cluster.
Several features supported by the 3174 controller determine special host
programming needs. For example, the Intelligent Printer Data Stream requires
support from host-related programs.
The feature sections and last chapter of this book offer more information about
programming support.
Chapter 1. Introducing the 3174 Establishment Controller
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