Final answer:
The standard MIDI connector uses 5 pins, but only two of them (pins 4 and 5) are used for MIDI data transmission.
Step-by-step explanation:
The standard MIDI (Musical Instrument Digital Interface) connector uses 5 pins. However, not all 5 pins are used for transmitting MIDI data. Pins 1 and 3 are not connected, pin 2 is connected to the shield and serves as the ground, and only pins 4 and 5 are used for MIDI data transmission with pin 4 being for MIDI data delivery and pin 5 being for data reception.