Communications Package Features; Hardware Features - Texas Instruments 990 User Manual

Introduction
1.3 COMMUNICATIOOS PACKAGE FEATURES
The communications package supports the following:
*
*
*
Communications between applications programs installed
in the primary station and those installed in secondary
stations.
Downloading of secondary stations from the primary
station. For TX5 secondary stations, the Model 990/5
Comp.lter must
be
equipped wi th an DXlO HDLC
Communications Package ROM loader.
Remote System Command Interpreter (SCI) capabilities for
installing applications programs in TXS secondary
stations from the primary station and debugging these
programs from a terminal at the primary station.
In order to perform these functions, the communications pac kage
includes hardware and software additions to both the primary
station and TX secondary stations. These additions are described
in the following paragraphs,.
1. 3 • 1 Har dw ar e F ea t ur e s
The hardware addi tions requi red by the communications pac kage
include the FCCC board for the primary station and an LLM for
each TX5 secondary station in the network. The FCCC board and
LLMs provide the following:
*
Bit-oriented, half-duplex, serial synchronous operation
that can be a maximum of 9600 bits per second
*
Mu1 tipoint operation
*
Eight-bit character length
* Switch-selectable addresses (on LLM)
* Line term ina t ion s el ect i on (on
LLlvI)
* Line iso1 ati on at a maximum of 1300 vol ts dc
* Dat a tr ans parency
*
l6-bit cyclic redundancy check (CRC-CCITT) to detect
line errors
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