My report like this below
0x05, 0x0C, // Usage Page (Consumer)
0x09, 0x05, // Usage (Consumer Control)
0xA1, 0x01, // Collection (Application)
0x85, 0x02, // Report Id (2)
0x15, 0x00, // Logical minimum (0)
0x25, 0x01, // Logical maximum (1)
0x75, 0x01, // Report Size (1)
0x95, 0x01, // Report Count (1)
0x09, 0xCD, // Usage (Play/Pause)
0x81, 0x02, // Input (Data,Value,Relative,Bit Field)
0x0A, 0x83, 0x01, // Usage (AL Consumer Control Configuration)
0x81, 0x02, // Input (Data,Value,Relative,Bit Field)
0x09, 0xB5, // Usage (Scan Next Track)
0x81, 0x02, // Input (Data,Value,Relative,Bit Field)
0x09, 0xB6, // Usage (Scan Previous Track)
0x81, 0x02, // Input (Data,Value,Relative,Bit Field)
0x09, 0xEA, // Usage (Volume Down)
0x81, 0x02, // Input (Data,Value,Relative,Bit Field)
0x09, 0xE9, // Usage (Volume Up)
0x81, 0x02, // Input (Data,Value,Relative,Bit Field)
0x0A, 0x25, 0x02, // Usage (AC Forward)
0x81, 0x02, // Input (Data,Value,Relative,Bit Field)
0x0A, 0x24, 0x02, // Usage (AC Back)
0x81, 0x02, // Input (Data,Value,Relative,Bit Field)
0xC0 // End Collection
I can accept incomming call in Android , Use Play Key or Key "Media select Telephone" 0x8C .But this can not work in IOS10.3.1. In IOS PLAY/PAUSE/PRE TRACK/NEXT TRACK/VOLUME INCREMENT/DECREMENT can work, But can not Answer call . I set the key code Based on the doc USB HID usage table. I have checked in this forum and Google for server days .