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Chapter 4. Protocol Conversion Mode
This chapter describes the 3708's protocol conversion (PC) mode of operation. It
includes a description of:
• The data flow through the 3708 in PC mode
• The data stream that the 3708 receives from the SNA host
• The data stream that the 3708 sends to the display or printer
• The configuration options that affect protocol conversion mode
• Displays and printers operating in PC mode.
This chapter also discusses the local copy function and displays with printers.
Data Flow in Protocol Conversion Mode
When operating in protocol conversion mode, the 3708 appears to the host as a 3270
controller with attached 3270 devices. The devices attached are either ASCII
displays or ASCII printers. The 3708 receives data from the host in 3270 data
stream format (LU type 1 SNA character stream (SCS), LU type 2, and LU type 3
Data Stream Compatibility (DSC) mode). The 3708 interprets the 3270 data stream
and converts it into commands that the attached ASCII device understands. Also,
the 3708 translates the EBCDIC characters to ASCII characters. (Translation is
required. However, translation may be done using one of the two standard 3708
translate tables, or a user-defined translate table. Selection of the standard user
table is optional and is set at configuration time).
Figure 4-1 on page 4-2 shows how data flows through the 3708 in protocol
conversion mode.
Note: Refer to Appendix E, "Key Data Formats and Control Blocks" for a
description of device buffers, system buffers, and receive queues.
Chapter 4. Protocol Conversion Mode
4-1
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