1.1 COMPUTER COMMUNICATIONS CATEGORIES

 

• Basic Categories

• Interface to Sensors and Actuators

- Uses readings from sensors to control devices in the environment

- very simple protocols, but often requires specialized hardware and software.

• Interface to computers

- uses machine to machine connection for direct communication

- can appear to be like a local area network

- low speeds (eg. 300 baud, 1.2, 2.4 9.2 Kbaud)

• Local Area Computer Networks

- measured in distances from meters to kilometers

- speed measured in Megabits/sec

- medium includes, wire, fibre-optics, radio frequency

- commonly available in all forms

- inexpensive

• Wide Area Computer Networks

- from city wide, to global

- speed measured in Kilobytes/second

- medium includes, wire, fibre optics, satellite, microwave

- access is costly (some mix of initial and variable costs), and geared to large corporations, or special applications.

 

• Classification of Interconnected processors (by Physical Size)

Table 1:

Inter-processor Distance	Processors Located in Same	Example
0.1 m	Circuit Board	Data flow machine
1 m	System	Multi- processor
10 m	Room	Local network
100 m	Building
1 km	Campus
10 km	City	Long haul network
100 km	Country
1000 km	Continent	Inter- connection of long haul networks
10000 km	Planet