1.
COMMUNICATIONS

2.
INTRODUCTION
• Parallel Port Vs. Serial Port
High Speed - Low Speed
Unidirectional - Bi-directional
Printers - Mice, Networks, Modems Etc
25 Pin Connectors - 9 Pin Connectors
• Provided As Extras on Add-on Cards
• Topics Covered in This Chapter
1. Serial Cards for Multi-user Systems
2. Networks

3.
SERIAL CARDS FOR MULTI-USER
SYSTEM
• Multi-user System - VDUs Serially Connected
“ The Systems in Which One Processor Is Shared by Many Users Are
Called Multi-user Systems.”
• Multi-port Intelligent Cards
• Blocking Technique
“ Large Chunks of Data Can Be Sent to the Intelligent Serial Board
by the Main Processor Where the Local Processor Can Pass Out
the Data One by One.”
• Intelligent Serial Ports Support All Types of Buses
• Also Needed for Multi-modem Dial-in Access

4.
NETWORKS
• Types of Networks
1. LAN
2. WAN
3. Intra-nets
4. Internets
• Ingredients of Networks
1. Network Operating System (NOS)
2. Network Adapter
3. Connecting Cables
• Issues in Data Transmission Speeds
1. Quality of Cable
2. Data Transfer Rate of Adapter
3. Direct Data Handling Capability of Computer

5.
NETWORKS.......Continued
• Types of Cables
1. Twisted Pair (1 Mbit/s)
2. Coaxial Cable (10 Mbit/s )
3. BNC Cables (10-15 Mbit/s)
4. Fibre Optic Cables (upto 1 Gbit/s)
• The Requirement of Data Handling to Be Kept in Mind
While Selecting the Type of Network Hardware and
Software
• Servers - Large Data Handling Requirement
Workstations - Small Data Handling Requirement