I can not connect Digital to analog converter (USB) for Mac OS X

Question

good afternoon

I can not connect the device

Here the data on it:

Full Speed device @ 5 (0x14200000): Composite device: "FT240X USB FIFO"

Port Information: 0x001a

Not Captive

Attached to Root Hub

External Device

Connected

Enabled

Number Of Endpoints (includes EP0):

Total Endpoints for Configuration 1 (current): 3

Device Descriptor

Descriptor Version Number: 0x0200

Device Class: 0 (Composite)

Device Subclass: 0

Device Protocol: 0

Device MaxPacketSize: 8

Device VendorID/ProductID: 0x0403/0x6015 (Future Technology Devices International Limited)

Device Version Number: 0x1000

Number of Configurations: 1

Manufacturer String: 1 "FTDI"

Product String: 2 "FT240X USB FIFO"

Serial Number String: 3 "DA6LXJK"

Configuration Descriptor (current config)

Length (and contents): 32

Raw Descriptor (hex) 0000: 09 02 20 00 01 01 00 80 2D 09 04 00 00 02 FF FF

Raw Descriptor (hex) 0010: FF 02 07 05 81 02 40 00 00 07 05 02 02 40 00 00

Unknown Descriptor 0020:

Number of Interfaces: 1

Configuration Value: 1

Attributes: 0x80 (bus-powered)

MaxPower: 90 mA

Interface #0 - Vendor-specific "FT240X USB FIFO"

Alternate Setting 0

Number of Endpoints 2

Interface Class: 255 (Vendor-specific)

Interface Subclass; 255 (Vendor-specific)

Interface Protocol: 255

Endpoint 0x81 - Bulk Input

Address: 0x81 (IN)

Attributes: 0x02 (Bulk)

Max Packet Size: 64

Polling Interval: 0 ms

Endpoint 0x02 - Bulk Output

Address: 0x02 (OUT)

Attributes: 0x02 (Bulk)

Max Packet Size: 64

Polling Interval: 0 ms

when it is connected to the system should appear in the external (USB) audio device on which to send the sound settings what should I do? write your kext? if so, how? where to start at all?

the manufacturer's website no drivers

Answer 1

A comprehensive answer to this question could probably fill a small book, but I'll try to give you some starting points.

1. USB Device Class Definition for Audio Devices

If the audio device adheres to the standard USB Audio Device class, but for some reason doesn't advertise this in the standard way, you can probably still use Apple's driver for such devices, by creating a codeless kext, or possibly a very small kext with some helper code.

There are a lot of details to this which Apple documents in TN2274 here.

2. Nonstandard USB audio

If your device uses a custom USB audio interface, you'll need to write your own driver. The kernel side API for this, IOAudioEngine etc. is actually deprecated since OSX Yosemite, with Apple recommending to write userspace Audio drivers instead. They provide some extensive sample code for getting started with this. Note that USB devices can be driven entirely from user space, so you don't even need a split USB/kernel driver architecture like you would for a PCI audio device.