The U6 has 3 different I/O areas:
- Communication Edge: Has a USB type B connector.
- Screw Terminal Edge: Convenient connections for 4 analog inputs, both analog outputs, 4 flexible digital I/O (FIO), and both current sources. The screw terminals are arranged in blocks of 4, with each block consisting of Vs, GND, and two I/O. Also on this edge are two LEDs. One simply indicates power, while the other serves as a status indicator.
- DB Edge: Has 2 D-sub type connectors: a DB37 and DB15. The DB37 has some digital I/O and all the analog I/O. The DB15 has 12 additional digital I/O (3 are duplicates of DB37 I/O).
USB: All power and communication is handled by the USB interface.
LEDs: The Power and Status LEDs convey different information about the device.
GND/SGND: All GND terminals are the same. SGND has a self-resetting thermal fuse in series with GND.
VS: All VS terminals are the same. These are outputs that can be used to source about 5 volts.
10UA/200UA: Fixed current sources providing 10µA/200µA at a max voltage of about 3 volts.
AIN#: AIN0-AIN13 are the 14 analog inputs.
DAC#: DAC0 & DAC1 are the 2 analog outputs. Each DAC can be set to a voltage between about 0.02 and 5 volts with 12-bits of resolution.
FIO#/EIO#/CIO#/MIO#: These are the 20 digital I/O, and are also referred to as DIO0-DIO19. Besides basic digital I/O operations, some of these terminals can also be configured as Timers & Counters (frequency input, PWM output, etc.), SPI serial, I2C serial, and Asynchronous serial.