1. Two Ways to Think About Connected Systems Architectures and Connections Architectures range from fully centralized to fully distributed. Centralized are typically master-slave connections while distributed are typically multiple access peer to peer. Somewhere in the middle is the client- server paradigm.

2. Centralized vs. Distributed Advantages of each Disadvantages of each

3. Relationships Between Computers Master-Slave –one is in control, one does what it is told Client-Server –both are autonomous –server provides some 'service' or resource to the client Peer-to-Peer –both are equals

4. Line Configurations Line configuration – the way in which two or more devices attach to a link Link – physical path over which data is transferred Types of Line configurations –Point to Point –Multipoint

5. LINK POINT TO POINT

6. MULTIPOINT LINE

7. TOPOLOGY Topology –Physical configuration of connection of devices –Example topologies Mesh Star Tree Bus Ring Hybrid

8. TRANSMISSION MODES Defines direction of information flow Types of transmission modes –Simplex –Half Duplex –Full Duplex

9. HALF DUPLEX Single, shared physical medium Information can flow in either direction Information flows in one direction only at a given time.

10. FULL DUPLEX Two independent channels (physical media) Information flow in both directions simultaneously

11. RS232C DTE DCE DTE Generates Data Converts to transmission media/ converts to generated data Receives Data (Network) DCE Converts to transmission media/ converts to generated data

12. RS232C u 25 pins assignments

13. RS232C – DB9 1 - carrier detect 6 – DCE ready 2- Receive7 – RTS 3 – Transmit 8 – CTS 4 – DTE ready9 – Ring Indicator 5 - SG

14. Null Modem