You can create a number of different types of virtual channels, depending on the signal type—analog, digital, or counter—and direction (input or output). These channels can be either global virtual channels or local virtual channels. For information on specific functions/VIs, refer to the NI reference help for your ADE.
A port-based channel represents a fixed collection of lines on the device. Reading or writing to a port affects all the lines on the port. The number of lines in the port (commonly referred to as port width) is hardware dependent and typically varies from 8 lines (MIO device) to 32 lines (SCXI digital modules).