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
38th parallel structures 38th parallel structures The 38th parallel structures, also known as the 38th parallel lineament, are a series of circular depressions or deformations stretching 700 km (435 mi) across southern Illinois and Missouri into eastern Kansas at a latitude of roughly 38 degrees north. Rampino and Volk (1996) postulated that these structures could be the remains of a serial meteorite strike in the late Mississippian or early Pennsylvanian periods. Difficulty in determining the age of many of the structures and doubts about the exogenic origins of several of them leave some geologists skeptical of this hypothesis. As of 2016, only two