1. CHAPTER Mainframe/Mini Related Communication Equipment

2. Chapter Objectives
Present mainframe and minicomputer related communication hardware that has not been presented elsewhere
Front-end processors, concentrators, protocol converters etc.
Describe the different types of terminals such as the ASCII and EBCDIC terminals, smart terminals etc.
Present examples of the use of the above equipment in practice

3. Chapter Modules
Mainframe Data Communication Equipment: Front End Processor and Concentrator
Minicomputer Data Communication Equipment: Communication Controllers
Protocol Converters
Data Terminal Equipment

4. END OF CHAPTER INTRODUCTION

5. MODULE
Mainframe Communication Equipment: Front End Processor and Concentrator

6. Definition of DCE and DTE
Data Communication Equipment
DTE
Data Terminal Equipment

7. DCE and DTE in the Real World
Mainframe
Computer
Printers,
Terminal etc.
DCE
DTE
Front End Processors, Concentrators,
Protocol Converters etc.

8. Some Mainframe Communication Equipment
Front End Processors
Manages the network traffic in a mainframe environment
Multiplexers
Discussed in an earlier chapter in detail
Communication controllers
Controllers, concentrators etc.

9. Mainframe Communication Equipment (Cont.)
Protocol converters
Used for linking devices that operate under a different protocol - different from the mainframe protocol

10. Overview of Communication Controllers
Used extensively in mainframes
3270 controllers for IBM mainframes
Level of sophistication
On one end of the spectrum is the front end processor
On the other end is the communication controller
There are also the other intermediate communication controllers and devices that are grouped under the family of communication equipment

11. Front End Processors (FEPs)
Computers by themselves
Connected to a mainframe for the purpose of managing the network traffic
FEPs reduce the load on the CPU
Enable the CPU to perform its primary task of running applications
FEP is a comprehensive DCE
Minicomputers, modems, LANs etc. can be attached to the mainframe through the FEP

12. A Front End Processor Connection
External Lines
Mainframe
Ter.
Ter.
Front End Processor
Mini-
Computer
Modem
Server
Gateway
Concentrator
LAN
Term.
Term. PC PC

13. END OF MODULE

14. MODULE
Minicomputer Data Communication Equipment: The Communication Controller

15. Communication Controllers for Minicomputers
In the case of the minicomputer, the controllers can be of the internal or external type
If they are internal controllers, they are installed in the expansion slot of the minicomputers
Manages the network traffic among the host, DTE and DCE

16. Controllers for AS 400 Known as the 5250 controllers
Fall under the 5250 family of DCE
Compare this with the mainframe’s 3270 family of DCE

17. Connecting DTE to a Communication Controller
ASCII
Printer
ASCII
Terminal
5250
Communication
Controller HP
Plotter
AS 400
Modem

18. AS/400 Connection to Terminal Equipment
AS/400 with
Built-in Communication
Controller
AS/400 Terminal
Equipment
Source: Black Box

19. AS/400 LAN Connection Server OS/400 PC AS 400 Plotter OS/2 PC Printer
Modem Pool

20. AS 400 LAN Connection Practical Example
Remote AS 400
Central Unit
Source: Black Box

21. In Summary
Two different ways by which a minicomputer can be connected to other devices including the DTE
Connect the terminal equipment directly to the minicomputer through its communication controller
Link the mini to its terminal equipment over a LAN

22. END OF MODULE

23. MODULE
Protocol Converter

24. Definition and Use
A protocol converter can be defined as an equipment used for interfacing systems working under different protocols
Protocol converters are most widely used for connecting peripheral devices to hosts
An example is the connection of ASCII terminals to IBM mainframes

25. ASCII and EBCDIC Terminals
Standard terminals used with the IBM mainframe
Code conversion difference is present between the EBCDIC and ASCII terminals
A protocol converter is required when an ASCII terminal is to be linked to an IBM mainframe

26. ASCII Terminal Link to an IBM Mainframe
Modem
IBM
3274
Controller
Protocol
Converter
PSTN To
IBM
Mainframe (FEP)
ASCII Terminal

27. Use of Protocol Converter to Connect ASCII Equipment to IBM Mainframe
ASCII Printer
PC (ASCII) Terminal
Source: Black Box

28. Mainframe Modem Connection
To IBM
Mainframe
Unix
Computer
Remote PC
Source: Black Box

29. Protocol Converter Used in Mini Computer Connection
ASCII
Printer
ASCII
Terminal
AS 400 HP
Plotter
Twinax
Multi-port
Protocol
Converter
Modem

30. Protocol Converters:AS/400 to ASCII Connection
Source: Black Box

31. Protocol Converter: AS400 to LAN and Printer Connection
Source: Black Box

32. Preferred AS 400 Connection to a LAN
Network
Interface Card
LAN PC

33. In Summary Frequent Usage
Connecting ASCII equipment to computers that operate under a different protocol
Utilized for connecting DTE to the mini and mainframe computers

34. END OF MODULE

35. Data Terminal Equipment (DTE)
MODULE
Data Terminal Equipment (DTE)

36. EBCDIC and ASCII Terminals
IBM mainframes
ES 9000 series
IBM minis
AS 400 series
ASCII
Popular in the Unix environment
IBM RS 6000 Unix computer
DEC computers running the Unix OS
Most recognizable ASCII terminal is the VT 100 terminal

37. Initial (Dumb) Terminals
Mainframe
Dumb
Terminals
Only involved in conveying the information between
the mainframe and the terminal.

38. Smart Terminals
Smart terminals are likely to incorporate reasonably powerful processors within themselves
They are able to perform local processing such as the local editing of information on the screen

39. Dumb Terminals Do not have processors for local processing
They rely on the host to perform most operations
Overloading the CPU is not a desirable course of action
The use of dumb terminals is on the decline

40. Microcomputer as a Terminal
There are two methods by which a microcomputer can be connected to a mainframe to act as a terminal
One involves a direct connection to a concentrator
Terminal emulation hardware and software are required for terminal emulation
The alternative method is to connect a LAN consisting of microcomputers to the mainframe

41. Micro as a Terminal: Direct Connection
Terminal Emulation
Software
IBM
Cluster
Controller.
Micro
Terminal
Emulation
Board
To IBM
Mainframe (FEP)

42. IBM Terminal Emulation
Source: Black Box

43. Gateway or similar device
LAN Based Connection
Terminal Emulation
Software PC PC PC
Gateway or similar device
Main
Frame PC
FEP

44. RS 6000: Native ASCII Connection
Terminals
AIX (Unix) Computer
Source: Black Box

45. In Summary Two major types Smart and Dumb terminals
ASCII and EBCDIC
Smart and Dumb terminals
Smart terminals engage in local processing
Microcomputers are increasingly being used to emulate the terminals

46. END OF MODULE

47. END OF MODULE END OF CHAPTER