1. A magnetic stripe reader (MSR) attachable to a personal digital assistant (PDA), the PDA having a data display, a synchronization port and hot sync capabilities, the MSR comprising: (a) means for reading and decoding data on a magnetic stripe; (b) means for transferring electric power from the PDA to the MSR and for exchanging data between the MSR and the PDA through the PDA synchronization port; and (c) means for managing electrical power consumption that control an automatic startup of the MSR for reading and decoding data on a magnetic stripe upon detecting encoded data on the magnetic stripe.