JK0-U31 Free Dumps Study Materials
Question 2: Which of the following ports on a computer are used to connect a keyboard? Each correct
answer represents a complete solution. Choose two.
A. USB
B. DB-25
C. PS/ 2
D. DB-9
Correct Answer:A, C
Explanation:
The PS/ 2 and USB ports on a computer are used to connect a keyboard. What is USB? Universal
Serial Bus (USB) is a high speed bus standard developed by Compaq, IBM, DEC, Intel, Microsoft, NEC,
and Northern Telecom. It provides the Plug and Play capability of Windows to external hardware
devices. USB supports hot plugging, which means that a USB device can be installed or removed
while the computer is running. A single USB port can be used to connect up to 127 peripheral
devices, such as CD-ROM drives, tape drives, keyboards, scanners etc. USB 1.1 has a maximum data
transfer rate of 12 Mbps, whereas USB 2.0 has a maximum data transfer rate of 480 Mbps. USB 2.0
is fully backward compatible with USB 1.1. Answer options D and B are incorrect. The DB-9 and
DB-25 port types on the computer are used as serial ports. A DB-9 male type port has 9 pins,
whereas a DB-25 male type port has 25 pins. What is a serial port? Serial port is the primary means
for connecting modems and mouse to a computer. There are two types of serial port connectors,
9-pin and 25-pin. The word serial refers to the data is sent in series, one bit at a time, over a single
wire. This design is significantly slower than sending 8 bits at a time via a parallel channel, but serial
signals can travel much farther without degradation.