User's Manual

Chapter 1 Overview

Chapter 1: Trace MMI Overview

The Trace ® Mini-Mobile Interrogator (MMI) is a portable data retrieval and storage

system designed to provide remote meter reading in conjunction with the Trace meter

transponders. The Trace system is designed to convert the mechanical index reading of a

utility meter to a duplicate electronic register reading. This electronic register reading is

transmitted via radio frequency (RF) signals to the MMI. The Trace MMI reads each

transponder by use of an RF interrogation that consists of a unique serial number along

with a command requesting the contents of the electronic register. Each transponder is

selected for reading on either a first-in-first-out (FIFO) basis, a latitude/longitude (L/L)

basis, or a combination of the two GEO mode. The MMI obtains route data from a

customer supplied floppy disk containing the street address, latitude/longitude , and serial

number of each transponder that is to be read.

The MMI uses a GPS-based navigation system that tracks the vehicle position. If the

Lat/Lon mode of interrogation has been selected, whenever the MMI comes into the

range of a particular transponder it begins to send an interrogation for that unit. When

the transponder receives a signal with the correct serial number it transmits its electronic

The MMI listens for each transponder reply using an 8-channel receiver. Reply data

integrity is confirmed by monitoring receiver data tracking signals and by an error

detection code known as a BCH code. A transponder reply is only accepted if the BCH

code analysis is valid. This ensures that the data was received without error. The meter

reading along with transponder status, receiver channel activity, time of the read, and

vehicle position at the time of the read is stored in an output file contained on a floppy

disk. Once the MMI has been initialized with the appropriate route data, the system will

collect readings automatically, allowing the operator to drive the route in a safe and

efficient manner.