On the other hand alphanumeric keys allow freeform entry of messages. At first glance Vehilce tracking marketplace may seem to offer a host of communication technologies for vehicle tracking applications. However, just by taking into account the application requirements one or two technologies mat come into focus. The requirements mainly cover aspects such as reporting rate, throughout capacity geographic coverage and cost. To date, the most common type of communication system used for tracking has been the conventional radios.
Conventional radios are portable and can handheld units or dashboard mountable units.
They are intended to operate in defined geographical regions. Users of these radios share a common radio channel and compete for airtime. As a result, RF collisions can occur if two users transmit at the same time. To curb collisions, a radio etiquette must be established wherein the users must monitor a channel and announce a line clear before attempting a call. Hence only a half duplex radio will suffice.