3.1 Serial Line
A PC has connectors for the COM1 and COM2 serial interfaces usually on the back. COM1 is commonly used for a mouse; hence after the serial line has been connected to our PC, only COM2 is left. The serial interface is usually used for connecting the modem.
Serial PC outputs use signals specified by the ITU-T V.24 standard (corresponding to the US standard—RS-232). It is an interface for serial asynchronous arrhythmic data transport. It is usually used for rates up to 64 Kbps although, you are most likely to connect your modem at home using 115,200 bps, and surprisingly, it is going to work well.
3.1.1 Serial and Parallel Data Transport
Serial transmission means that there is only one pair of wires (or one wire and a shared ground for asymmetric interfaces) for transporting information from the sender to the receiver. Therefore, the individual bits of every single character are transported following each other, i.e., serially.
Parallel transmission uses eight wires (or...
