How can I transfer data to HID if it has not OUT Endpoint - hid

Question

I am trying to implement data exchange with some HID device. I managed to implement reading from this device using libusb_interrupt_transfer function, but I do not know how to implement sending a buffer to the HID, because device has not OUT endpoint. How can I transfer data to HID? Descriptor of device looks like this:
Bus 001 Device 074: ID 16d0:8080 MCS
Couldn't open device, some information will be missing
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 1.10
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x16d0 MCS
idProduct 0x8080
bcdDevice 2.03
iManufacturer 1
iProduct 2
iSerial 3
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 34
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xc0
Self Powered
MaxPower 500mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 3 Human Interface Device
bInterfaceSubClass 0 No Subclass
bInterfaceProtocol 0 None
iInterface 0
HID Device Descriptor:
bLength 9
bDescriptorType 33
bcdHID 1.11
bCountryCode 0 Not supported
bNumDescriptors 1
bDescriptorType 34 Report
wDescriptorLength 32
Report Descriptors:
** UNAVAILABLE **
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0008 1x 8 bytes
bInterval 5

Answer 1

If the device doesn't have an OUT endpoint, the only way to send data to the device is using control transfers using default control endpoint (EP0).
There are HID class specific control requests mentioned in the HID Specification document. However, SET_* requests aren't mandatory, so your HID device may not support them.
There can be also vendor specific control requests, but there is no way to guess them, so they need to be documented by the device vendor.