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