Page 88 - Intelligent Communication Systems

CHAPTER 7/NEWLY DEVELOPED TELECOMMUNICATION SERVICES 71
definitions of data, description methods, sequences of transmission, and the lay-
outs of data components.
(2) Rules for information interchange and sharing: Items are specified, which
include the time, frequency, and priority of information interchange, the certifica-
tion of information interchange, the acknowledgment of information, security, and
database specifications.
(3) Related software: There is a software that converts documents written by
means of word processors to those specified by SGML,

7.8.6 Prerequisites for Information Sharing
Three elements of CALS have to be considered to establish information sharing:
the digitization of information, standardization, and the open system approach.
Generally speaking, data formats, specifications, communication methods, and
protocols differ among companies or institutions. In these situations, it is difficult
to share information among the different organizations. But by using CALS, dif-
ferent companies can share information by interconnecting via communication
networks.
To share information, it is appropriate to digitize the information, including
not only text but also figures, images, voice, and motion pictures. Information has
to be digitized in the process of manufacturing, including design, development,
manufacturing, sales, and maintenance. Conventional digitization of information
had not been standardized, but was done by using the computers or systems that
system integrators had. Digitization depended on the specific computers or sys-
tems, so it was difficult to exchange information. Via the introduction of CALS,
the formats for information and communication protocols have been standardized.
By taking the three elements—digitization, standardization, and the open system
approach—into consideration, it is easy to exchange information among different
companies.
In order to implement CALS, it is important to construct an integrated data-
base (IDB) that serves the functions of information retrieval in digital form. IDB
is a distributed database linked over the network. By means of IDB, information
that is distributed over the network can be shared.

7.8.7 Standardization of CALS
The standards that have already been established are introduced as the elements of
CALS. The specifications that have been standardized by international organiza-
tions of standardization, such as ISO, are studied first. Second, the specifications
that have been standardized by domestic standardization organizations, such as
ANSI, are studied. Third, the specifications that have been used widely in the pri-
vate sector as de facto standards are studied. If there are no models for stan-
dardization of CALS, the company studies its own specifications for standards.