Chapter 16
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bFunctionLength 0x05 Descriptor size in bytes (5)
bDescriptorType 0x24 CS_INTERFACE
bDescriptorSubtype 0x01 Call Management Functional Descriptor
bmCapabilities 0x00 Device doesn’t handle call management itself
dDataInterface 0x01 Interface used for call management (bInterfaceNumber of a
data class interface in this configuration).
bLength 0x07 Descriptor size in bytes (7)
bDescriptorType 0x05 Descriptor type (ENDPOINT)
bEndpointAddress 0x82 Endpoint number and direction (2 IN)
bmAttributes 0x03 Transfer type (interrupt)
wMaxPacketSize 0x0008 Maximum packet size (8)
bInterval 0x02 Maximum latency
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bLength 0x09 Descriptor size in bytes (9)
bDescriptorType 0x04 Descriptor type (INTERFACE)
bInterfaceNumber 0x01 Interface Number
bAlternateSetting 0x00 Alternate Setting Number
bNumEndpoints 0x02 Number of endpoints in this interface
bInterfaceClass 0x0A Class (data)
bInterfaceSubClass 0x00 Subclass code (no subclass)
bInterfaceProtocol 0x00 Protocol code (no class-specific protocol)
iInterface 0x00 Interface string index (no string defined)
bLength 0x07 Descriptor size in bytes (7)
bDescriptorType 0x05 Descriptor type (ENDPOINT)
bEndpointAddress 0x81 Endpoint number and direction (1 IN)
bmAttributes 0x02 Transfer type (bulk)
wMaxPacketSize 0x0040 Maximum packet size (64)
bInterval 0x00 Maximum latency
(doesn't apply to full-speed bulk endpoints)Table 16-3: Example descriptors for a full-speed CDC device (Sheet 3 of 4).