Subscriber set and telematics

When the telematics gets started, the structure of the subscriber set has got to be reconsidered. However, two aspects should be retained The energy wasted and the other complications caused by microphone current (20 or 40 mA at 48 volts, i.e. 1,5 Watts dissipated in the carbon of microphone) can be avoided. This is possible by the use of piezoelectric microphone with an incorporated amplifier, which offers a more economical solution. The second yery useful objective to be attained is the possibility of doing analog-digital conversion and vice-versa alongwith the associated filteration operations in the subscribers\´ set itself, This way, the transmitted signals in bureautics and telematics would become digital signals. The resulting increase in the flow rate of lines could be useful in increasing the efficiency of different services. So that, the problem of realizing cheap "MODEMS" which is very difficult to solve, would dissapear.