IEEE 802.3 Working Group - SCC14

The following is a summary of various comments received over time from SCC14 in respect to formatting:

Physical quantities

The letter symbols for physical quantities, mathematical variables, indices and general functions (as opposed to mathematical functions), are always printed in italic. Some examples are:

I       for electrical current
i,j,k   for indices
f(x)    for f function of x

Units

The letter symbols for units are always printed in upright font. Some examples are:

A       for ampere
m       for meter

Mathematical operators and functions

Mathematical functions and operators are always printed in upright font.

+       for addition
tan     for tangent
log10    for logarithm to base 10

Mathematical and physical constants

e       for base of natural logarithms
j       for imaginary unit
p         for the ratio of the circumference of a circle to its diameter

c       for speed of light in a vacuum
g       for acceleration of gravity

Multiplication

The asterisk is never to be used in text or equations in technical writing to indicate multiplication. Computer programs are another matter, of course. Multiplication of quantity symbols is indicated simply by printing them next to each other. Multiplication of units is indicated by use of a multidot. Multiplication of numbers is indicated by use of a multiplication symbol. Some examples are:

ab
A.h     for ampere hour
MHz·km  for megahertz kilometres
2 × 3

Numbers

Numbers that appear in equations or with quantity symbols or unit symbols are printed in upright font. With unit symbols, a space is left; with quantity symbols, this is no space. Some examples are:

12 kV   for twelve kilovolts
2I      for two times a current I

Subscripts and superscripts

Subscripts and superscripts and follow the same rules as above. Symbols for physical quantities, mathematical variables, indices and general functions are printed in italic. Some examples are:

2n      for 2 to the power of n
n2      for n squared
Ii        for input current (since the i is not a symbol for a variable)

Punctuation

All punctuation, including grouping symbols, such as parentheses, brackets and braces, are printed in upright font. Some examples are:

f(x)    for f function of x
n!      for factorial n