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A using the non-intelligent terminal protocol, A.1.1 nitp character set, Using the non-intelligent terminal protocol – Siemens SIMATIC TIWAY 1 User Manual

Page 177

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UNILINK HOST ADAPTER

A–1

USER MANUAL

APPENDIX A

USING THE NON-INTELLIGENT

TERMINAL PROTOCOL

A.1 CHARACTERISTICS OF THE NON–INTELLIGENT TERMINAL

PROTOCOL

The Non-Intelligent Terminal Protocol (NITP) is a simple, character-oriented
method of data link communications using standard 7-bit ASCII codes. Both
command and response messages consist of starting and ending delimiters, a
character count or message length field, the body of the message, and an
error-checking code field as illustrated in Figure A–1.

:

Character

Count

Message

Body

ECC

;

Figure A–1

NITP Message Structure

A.1.1

NITP Character Set

NITP uses the subset of standard ASCII codes, shown in Table A–1, to
communicate with a wide variety of host devices, from ASCII terminals to more
intelligent machines.