Is libusb the preferred method on Mac OS X to access USB device?

Is libusb the preferred method to talk to a device over USB (using AT commands) on OS X these days?

Is there any high level equivalent in cocoa?

Why use libusb?

Libusb allows you to enumerate devices and select the one you want based on a specific Vendor/Product id (V/P Id). If you don't know this and can't find it online with the product's description then you can easily find it. If it is not online you will need to use an app similar to lsusb on Linux.

What is Libusb Mac?

libusb is a library for USB device access from Linux, macOS, Windows, OpenBSD/NetBSD, Haiku, Solaris userspace, and WebAssembly via WebUSB.

On OS X, drivers are written using the IOKit and a subset of C++. More specifically, for USB devices, you probably want to start with Apple's USB Device Interface Guide and browse the USB parts of Hardware and Drivers section of the Mac OS X Core Library documentation set in XCode. (Edit: The latter resource is also available online.)