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 port serial ports in a PC. The only limitation is the amount of resources, such as operating memory and computing power, needed to emulate many serial ports at the same time. Virtual serial ports emulate all hardware serial port functionality, including baud rate, data bits, parity bits, stop bits, etc. Additionally, they allow controlling the data flow, emulating all signal lines (DTR, DSR, CTS, RTS, DCD, and RI) and customizing pinout. Virtual serial ports are common with Bluetooth and are the standard way of receiving data from Bluetooth-equipped GPS modules. Virtual serial port emulation can be useful in case there is