>Most other 'line' levels are 'flexible' adaptations of
>this standard. 1mW into 600 Ohms unbalanced is 0.775V rms
>or about 2.17V pkpk.

Various standards I recall.

0dbm into 600 ohm (balanced or unbalanced) is 1mW and gives around 0.775V
(as already mentioned) and generally used as the 0db marking on many meters.

0dbV uses 1Vrms as the 0db reference, impedance unimportant, all
measurements done in voltage only.
0dbmV as above, but using 1mV as reference
0dbW sometimes also used, using 1W into whatever impedance happens to be in
use as the reference.

The reference being used can usually be inferred from the "suffix" used, but
also it is common to talk in terms of db relative to the 0dbm voltage level,
without worrying about the impedance, i.e. using 0.775V as the reference.

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