prof. dr. m. h. assal a.s. 2/4/2014. the interfaces for attaching external devices to a computer or...
Post on 14-Dec-2015
214 Views
Preview:
TRANSCRIPT
A.S. 2/4/2014
5. Data Ports
Prof. Dr. M. H. Assal
Introduction to Computer
2
Data Ports The interfaces for attaching external devices to a
computer or The doors through which information enters and
leaves a computer system. and leaves a computer system.o PS/2 ports (Mouse, Keyboard)o Serial ports (Mouse, modems, printers) 150 kbpso Parallel ports (printers, scanners, external data drives) 1.2
mbpso SCSI ports – Small Computer Systems Interface
(many internal and external devices) up to 320 mbpso USB ports - Universal Serial Bus
(nearly everything) 1.5 - 12 - 480 - 4000 mbpso Firewire Connections (imaging devices – digital
camcorders, scanners) 100-800 mbps
3
Data Ports
PS/2 Ports Serial Port
Parallel Port
USB
SCSI
Firewire Ports
4
Data Port Features Fast Reliable Flexible Inexpensive Power-conserving Supported by the operating system
5
Parallel Port Commonly known as the printer port 25 pin D-Type connector It has 12 digital output pins, 5 digital input pins Pins operate at the TTL voltage level i.e. 0 – 5V Port identified by a base address in the computer
I/O memory space
7
Serial Port 9 pin D-Type connector Pins operate at -25 to +25 voltage levels Data transmitted as a bit sequence Known as the EIA RS232C port or simply
RS232 Maximum date rate of 19,600 bps
8
Serial Port vs. Parallel Port
Serial cables can be much longer than Parallel cables
Serial suited for wireless transmission
9
Universal Serial Bus Universal Serial Bus (USB) was designed in mid-
1990s to standardize the connection of computer peripherals to computers.
It has become commonplace on other devices (such as smartphones, PDAs and video game consoles).
USB has effectively replaced a variety of earlier interfaces, such as serial and parallel ports.
USB is a likely solution any time you want to use a computer to communicate with devices outside the computer
Device, male connector Computer, female connector Hub
10
Universal Serial Bus
Interface # of De-vices
(maximum)
Length(max feet)
Speed(max. bps)
Typical Use
USB 127 16 (or up to96 ft. with 5
hubs)
Ver. 1.0 1.5 M (nearly everything)Mouse,
Keyboard, Hard Drives, Mass Stor-
age, Network Adapters, Audio, Camcorders
Ver. 1.1 12 M
Ver. 2.0 480 M
Ver. 3.0 5 G
RS-232 2 50-100 20 K (115K with
somehardware)
Modems, MouseBar-Code ReadersInstrumentation
Parallel (Printer) Port
2 10–308 M
PrintersScanners
IEEE-1394 (FireWire)
64 15 IEEE-1394a
400 M
Digital Video (Cam-corders)
Old iPod & iPhoneMass StorageIEEE-
1394b 3.2 G
Comparison
12
Universal Serial Bus USB Features
Flexible Ease of use was a major design goal for USB, and the result is an interface that’s a pleasure to use for many reasons: Windows automatically detects the peripheral and loads the appropriate software driver.There’s no need to locate and run a setup program or restart the system before using the peripheral.
One interface for many devices. USB is versatile enough to be usable with many kinds of peripherals. Instead of having a different connector type and supporting hardware for each peripheral, one interface serves many.
SpeedUSB supports three bus speeds: high speed data transfer.
ReliabilityThe reliability of USB results from both the hardware design and the data-transfer protocols.
Low Cost
Low Power Consumption
Universal Serial BusIt’s Not Perfect
Lack of Support for Legacy HardwareOlder (“legacy”) computers and peripherals don’t have USB ports. If you want to connect a non-USB peripheral to a USB port, a solution is a converter that translates between USB and the older interface .
Distance LimitsUSB was designed as a desktop bus, with the expectation that peripherals would be relatively close at hand. A cable segment can be as long as 5 meters. You can increase the length of a USB link to as much as 30 meters by using cables that link five hubs and a device, using 6 cable segments of 5 meters each.
Peer to Peer CommunicationsUSB can’t talk to each other directly. All communications are to or from the host computer. Other interfaces, such as IEEE-1394, allow direct peripheral- to-peripheral communications.
13
14
Universal Serial Bus
USB 2.0 A big step in USB’s evolution was version 2.0.
Support for much faster transfers.
a 40-times increase was found to be feasible, for a bus speed of 480 Megabits per second.
USB 2.0 is backwards compatible with USB 1.1.
Version 2.0 peripherals can use the same connectors and cables as 1.x peripherals.
15
Universal Serial BusUSB 3.0
Released in November 2008 Also referred to as SuperSpeed USB Speeds 10x faster than 2.0 (5 Gbps in controlled test
environment) Extensible – Designed to scale > 25Gbps Optimized power efficiency Backward compatible with USB 2.0
o USB 2.0 device will work with USB 3.0 hosto USB 3.0 device will work with USB 2.0 host
16
Universal Serial Bus
Added pins for SuperSpeed USB signals.
Compatibility for USB 2.0 connectors.
Different shapes of connectors are provided to support the compatibility with current (USB 1 & 2) devices.
USB 3.0 Connectors
23
USB vs. Firewire (IEEE-1394)
USB Firewire
Multiple devices support
Single host can communicate with many peripherals/devices
127 64
Peer to Peer No Peer-to-Peer support
Support Peer-to-Peer model, where peripherals can communicate with each other directly
Cost Relatively Cheap Expensive
THANK YOU
top related