A duplex outlet is 115vac.
Yes, the feeder will have to be a three wire cable.
Seeing that the question comes from North America the most common duplex receptacle has 110 - 120 volts potential to ground. The second most common potential difference is 220 - 240 volts. These voltages are obtained from a 120/240 volt system common to home connections from the local utility companies.
Two-du plex
There are many companies that sell Duplex printers. Duplex printers are able to print on both sides of a piece of paper. Online purchasing options include companies like HP and Amazon. Retail stores such as Walmart will also carry a variety of Duplex capable printers.
45 volts
CAN is half-duplex. One differential pair means one message at a time.
Many do, some don't.
1000
230 Volts
duplex duplex
TCP is usually used as full duplex, but in some case, half duplex can also be used in TCP.
Full Duplex