RS232 serial communication is one of the oldest communication where data is sent or received one bit at a time. This protocol can easily be used to communicate between a PC and various devices supporting this type of protocol like PIC microcontrollers, GPS, GSM modem etc. While other interfaces like Ethernet, FireWire, and USB all send data as a serial stream, the term "serial port" usually identifies hardware more or less compliant to the RS-232 standard, intended to interface with a modem or with a similar communication device. MikroC Pro for PIC