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
Serial digital interface application and interoperability. An 8-bit parallel digital interface is defined by ITU-R Rec. 601; this is obsolete (however, many clauses in the various standards accommodate the possibility of an 8-bit interface). In SD and ED applications, the serial data format is defined to 10 bits wide, whereas in HD applications, it is 20 bits wide, divided into two parallel 10-bit datastreams (known as Y and C). The SD datastream is arranged like this: whereas the HD datastreams are arranged like this: For all serial digital interfaces (excluding the obsolete composite encodings), the native color encoding is YCbCr format. The luminance