This is a serial communications module (using the UART that exists inside the PIC 18Fxxx, It just changes Voltage levels so your 5v microchip, doesnt get fried by the serial’s +-9V
This is a simple 7805 on a perfboard. Giving stable 5v to your (my) test circuits and breadboard projects.. I recently made a 3.3 V version for experimenting with the dsPIC33 family.. (more problems with these to follow 
I have the same concept here. I have modules for lots of breadbording things: Serial, parallel port, USB, LCD (with contrast et al), power regulation…you name it! Spend some time in http://www.tabajara-labs.com.br and have fun
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