User's Guide

Teletrac, Inc. - Prism TM Information and Installation Guide
54 1622-0300 B1 3/18/04
Appendix D
APPENDIX D – HOW MESSAGES ARE USED IN SCRIPTS
Message Code Usage
General
NOTE: The term VLU means all Teletrac location units.
The purpose of this paper is to give guidelines on how to standardize message code usage
for Fleet Director, MDTs and VLUs. The standardization of message codes is intended
to help make it easier to develop and support customer applications. The following bullet
list expresses the basic reasons for message code standardization.
• Training – Standardization of codes make the code usage intuitive by using
the same codes for similar messages. This helps both the newcomer and the
trainer since code usage has common rules that easily understood.
• Customer Support – As in training the code standards make it easier to
support the customer when all customers are setup with common rules on
code usage. This avoids the confusion associated with have multiple customer
applications using similar messages but uncommon codes.
• Installation Support – By standardizing code usage standard workstation,
MDT and VLU configurations can be developed as packages with minimal
customization requirements. This prevents mistakes in application setup and
decreases the cost and time to install customer equipment.
• Code Conservation – Message codes are limited, especially for inbound
messages. All messages cannot be given unique. By standardizing codes,
commonly used messages can be given unique codes leaving the remaining
codes for reuse in new applications.
• Script Development – By developing standardized relationships for codes and
script features and VLU hardware, script development is made less costly.
Without standardization far more scripts would need to be developed for
different uses of the codes for similar functions or features. This would be
very confusing since most scripts would have minor differences and keeping
track of the difference would be difficult. Ultimately the support personnel
would standardize on script usage by using the script most familiar to them
thus achieving a similar affect as code standardization. Unfortunately
different installers would have different standards and engineering would still
have to produce large numbers of scripts to meet everyone’s expectations.
• System Development – As new system capabilities are developed along with
new workstation software and mobile equipment, the usage of message codes
play a part on service privileges and expectations. By standardizing codes, the
system can more easily be developed to handle ranges of codes or a selected