Techniques for location tracking, location utilization, and dissemination and management of location information are disclosed. According to certain embodiments, the originating user E-mails a web site or server of the paging system paging information, with the server then transmitting the paging message over a packet-switched digital data network to a receiving or terminating web site or server located in the different country. The hidden code can be detected by projecting a light source having the predetermined wavelength at a predetermined angle on the tag and using a sensor to sense the reflection from the tag. Then, for each detected arrhythmia, a determination is made based on the data, whether there was a myocardial ischemic episode detected within a specified temporal proximity of the arrhythmia. After receiving the transmitted signals, the first channel and the second channel of signals are regenerated in the receiver system by separating one from the other.