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How to connect TELIT GM862 module to the PICMICRO.

The application uses the connection between UART of the PIC and UART of the TELIT through Level Shifter (realized with 2 transistors NPN-PNP) in order to adapt signals to 5V of micro with those to 2V8 of the module. A BCR22PN could also be used as an example or a 74HC125 for transferring the signals from 2V8 -> 5V while from 5V -> 2V8 a diode in series with the cathode towards 5V and one resistance of pull up between anode and 2V8 (outgoing from the module PowerControl)
In a generalized manner for the Level Shifter it can be used also the CMOS buffer like 4049 (inverting) and the 4050 (not inverting).

Besides the current supply of the Telit Module has been realized with a ADJ regulator (LM350) with outgoing 3V8 in a position to support (through the condensers) the current of peak demanded from the module in the phase of hanging network.

Other alternative of current supply are: switching power pack or economic power pack with [ (5V) (2 DIODE VALVES) (3V6) ] but in this last case the condenser ability on the module current supply is decisive at least 2200uF