This operation returns a structure that describes the device. The first byte is set to an ioctype of DD_DLC. The subtype and data are defined by the individual DLC devices. See the /usr/include/sys/devinfo.h file for details.
The IOCINFO ioctl operation is selectable through the fp_ioctl kernel service or the ioctl subroutine. It can be called from the process environment only.
Generic Data Link Control (GDLC) Environment Overview in AIX Version 4.3 Communications Programming Concepts.