Standards
R2 signalling refers to a vast number of variants of R2 that resemble each other to varying degrees. For most R2 variants, each such variant of R2 is promulgated by the PTT of each nation and/or by a telecommunications equipment manufacturer who addressed that national market with a nation-specific adaptation of one of their products.
The international version of R2 is an inter-nation protocol for R2 signalling that crosses national boundaries, and is neither a superset nor a subset of any national variant of R2. Conversely, each national variant of R2 is intra-nation. The international standard R2 was first promulgated by CEPT in the 1970s and then later by ITU-T with only modest evolution.
Read more about this topic: R2 Signalling
Famous quotes containing the word standards:
“If one doesn’t know one’s own country, one doesn’t have standards for foreign countries.”
—Johann Wolfgang Von Goethe (1749–1832)
“To arrive at a just estimate of a renowned man’s character one must judge it by the standards of his time, not ours.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)
“With his brows knit, his mind made up, his will resolved and resistless, he advances, crashing his way through the host of weak, half-formed, dilettante opinions, honest and dishonest ways of thinking, with their standards raised, sentimentalities and conjectures, and tramples them all into dust. See how he prevails; you don’t even hear the groans of the wounded and dying.”
—Henry David Thoreau (1817–1862)