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NCJRS Abstract

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NCJ Number: 147846 Find in a Library
Journal: Journal of Forensic Identification  Volume:44  Issue:2  Dated:(March/April 1994)  Pages:139-144
Author(s): S Cain
Date Published: 1994
Page Count: 6
Type: Report (Technical)
Format: Article
Language: English
Country: United States of America
Annotation: Previous research found that no two telephones produce the same line transients when the telephone is picked up or hung up; the current study tested this hypothesis using the on/off hook transient signatures of 20 different telephones at an electronics store in Lake Geneva, Wisconsin.
Abstract: The recorder used to identify on/off hook transients was a Marantz PMD221 cassette recorder, and the same telephone intercept equipment and procedures were used throughout the tests. In an attempt to simulate forensic conditions, the researcher captured actual telephone company line noise artifacts simultaneously with on/off hook transient signatures. The Tektronix 2230 storage oscilloscope was used to obtain and display telephone line transient data, and captured transient waveforms were photographed. Results showed that on/off hook telephone transients were individually identifiable for each telephone. Further experiments are recommended to evaluate the effects of telephone line length, testing equipment, and time of day on transient waveforms. 2 references and 4 figures
Main Term(s): Science and Technology
Index Term(s): Criminal investigation; Criminalistics; Evidence identification; Forensic sciences; Police equipment; Telephone equipment; Wisconsin
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