If the user refuses, the next time the program loads, it will operate in trial mode until a valid serial number has been entered.
[5] In research computing, phoning home can track the daily usage of open source academic software.
This software employs an agent which calls into an Absolute-managed server on regular intervals with information companies or the police can use to locate a missing computer.
Such behavior, for example, caused v7.0.5 of Adobe Reader to add an interactive notification whenever a PDF file tries phoning home to its author.
Images and other files required by the e-mail body may generate extra requests to a remote web server before they can be viewed.
Surveillance cameras Foscam have been reported by security researcher Brian Krebs to secretly phone home to the manufacturer.