From Industrial Data Communications 4th Edition
In the text we look at the way data is represented (a set of patterns referred to as “1” or
“0”) generally in a set of these patterns called an octet or a byte (or sometimes a character
when referring to text), and we have looked at the abstraction of a model to see the functions
required to move these data representations from one end user to another. We will
now look at another of the fundamentals of communications, the medium over which we
transmit those data representations, the very bottom of the OSI Model, the media. This is the
location where the Physical layer attaches to the outside world, the conduit for information.
All things in data communications are related, and if they are all not correct you do not
communicate very well. Sometimes called pipes, the media is the main constraint on data
transfer speed. There are three types of media in general we will discuss, these are: the
copper types, fiber-optic types, and wireless types. Since this probably covers all media normally
used, that isn’t too restrictive. Of the copper types, three generally come to mind in
the LAN and industrial areas: the Unshielded Twisted Pair (UTP),...
Products & Services
Topics of Interest
14-1 General With the exception of the fact that gases are compressible the theory of design for equipment to move gases and vapors is similar to that of pumps for liquids. Heads developed in terms...
Fans, Centrifugal Besides being used in process plants, centrifugal fans are common in building heating and air-conditioning systems. Vendors for these systems should be consulted for required...
AIR HANDLING AND VENTILATION A fan is a gas flow producing machine which operates on the same basic principles as a centrifugal pump or compressor. Each of these devices, including fan, converts...
Symbols ? p = vapor pressure differential, in. Hg (kPa) ? T = temperature difference, F ( C) ? = efficiency, % v = specific volume, ft 3/lb (m 3/kg) ? = density, lb/ft 3 (kg/m 3) A = area, in. 2...
Era Period Epoch Millions of years ago Cenozoic Quaternary [*] Holocene 0.01 Pleistocene 0.01 1.8 Tertiary [*] Pliocene 1.8 5.1 Miocene 5.1 24.6 Oligocene 24.6 38.0 Eocene 38.0 54.9...