PIC Tutorial - RS232 Board
This is the RS232 board, it uses a MAX232 5V to RS232 converter chip, this converts the 0-5V TTL levels at the PIC pins to the +12V/-12V levels used in RS232 links. As is common with these devices it inverts the data during the conversion, the PIC USART hardware is designed to take account of this - but for software serial communications you need to make sure that you invert both the incoming and outgoing data bits.
The top two jumpers (Jmp1 and Jmp2) on the RB7 and RB6 lines are for connection to the 16F876 board (the 16F876 uses RC6 and RC7 for it's USART connection), and the tracks should be cut feeding RB1 and RB2, as in the third graphic below. The bottom two jumpers (Jmp3 and Jmp4) on the RB1 and RB2 lines are for the 16F628 board (the 16F628 uses RB1 and RB2 for it's USART connection), and the tracks should be cut feeding RB6 and RB7, as in the second graphic below.
So, for use with the 16F876 board cut the two tracks shown to RB1 and RB2, for the 16F628 cut the two tracks RB6 and RB7. This only applies if you are using the hardware USART, for software serial communications you can use any pins you like.
Although it's labelled as connecting to PortC for the 16F876 processor board (and is also designed to connect to PortB for the 16F628 processor board), as with most of the boards, it can also be connected to other ports if required, and if not using the hardware USART.