User's Guide

Teletrac, Inc. - Prism TM Information and Installation Guide
58 1622-0300 B1 3/18/04
Final Comments
The key to good standardization is to keep similar message grouped together and to make
the code usage intuitive. Unfortunately sometimes intuitive and grouping don’t mix. The
best standardization method would never use the same message code twice however we
don’t have that luxury due to limited code availability (especially on the inbound
messages). For Teletrac the best approach is to review our message code usage and
anticipate future needs. As we already know, some messages definitions are similar and
used by all customers (or nearly all-Ignition On/Off, VLU Sleep, etc.). These commonly
used messages should become standardized.
We also know that some messages are used for status, some for information and others
for control. We should try to group these three groups as best we can. Unfortunately,
some messages can’t fit neatly into standard grouping definitions due to either multiple
uses in the same installation (i.e. Panic might be in the MDT emergency menu and also in
the VLU for a hidden switch). When dealing with these conflicts its best to think of
installation support and script standardization. We don’t want to make it difficult on
support personnel when similar functions end up being different for each case.
Furthermore, if we keep changing which message is used for standard script functions
(input activity) we will end up with a lot of scripts with minor differences that will be
hard to track. For the above Panic message example it would be best to use the Input 2
message code ACM 53 for Panic in both the MDT and VLU so that the basic multi-input
script could work without changes and the installer knows that input two always causes
an ACM 53 message.