Serial port Yost standard combines DSR and DCD. Some serial ports on motherboards or add-in cards provide jumpers that select whether pin 1 of the DE-9 connector connects to DCD or a power supply voltage, and whether pin 9 of the DE-9 connector connects to RI or a power supply voltage. The power supply voltage can be +5V, +12V, +9V, or ground. (Selection varies by vendor.) The power is intended for use by point-of-sale equipment. Makers include Dell, HP, and others (This is not an official standard.) Operating systems usually create symbolic names for the serial ports of a computer, rather than
Parallel and counter parallel Parallel and counter parallel In music, a parallel chord (relative chord, German: "Parallelklang") is an auxiliary chord derived from one of the primary triads and sharing its function: subdominant parallel, dominant parallel, and tonic parallel. The term is derived from German theory and the writings of Hugo Riemann (see: Riemannian theory). For example, the major and and minor and . The parallel chord (but "not" the counter parallel chord) of a major chord will always be the minor chord whose root is a minor third "down" from the major chord's root, inversely the parallel chord of a minor chord will