211 will likewise include four pins data d pin and data d u2212 pin power and ground pins not shown for clarity for exemplary purposes the operation of high speed usb transmitter 210 is described with respect to the generation of half of the differential usb signal e g the d signal however it is understood that complementary usb signal generator circuitry 215 included in usb transmitter 210 can generate complementary signal d u2212 forming the other half of the differential usb signal in a manner substantially similar to that described below with respect to the generation of signal d note further that usb receiver 250 will also include a second resistor to ground not shown that is substantially similar to resistor 260 to receive the complementary d u2212 signal high speed usb transmitter 210 includes a voltage source 220 signaling circuitry 225 and a resistance element 230 voltage source 220 signaling circuitry 225 and resistance element 230 are connected in series between a ground terminal indicated by the inverted triangle and usb port 211 voltage source 220 provides a reference voltage vref which for reasons described in greater detail below is 0 8 v signaling circuitry 225 provides a switching output between voltage vref and.