reading user input by bios functions

What kind of user input exactly?
Keyboard:

Code:

    mov ah, 0 ; 88-key keyboard
    int 22 ; al = ascii code, ah = scancode
; or
    mov ah, 16 ; extended
    int 22 ; al = ascii code, ah = scancode

COM:

Code:

    mov ah, 0 ; initialize
    mov al, 11100011b ; 9600 boud / no parity / 8-bit sequence + 1-bit stop
    mov dx, COM_NUMBER ; 0 - 3
    int 20 ; al = model status, ah = line status
; and then
    mov ah, 3 ; receive
    mov dx, COM_NUMBER ; 0 - 3
    int 20 ; al = byte, ah = line status

Mouse:

Code:

    mov ax, 0xC200 ; activate / deactivate
    mov bh, 1 ; activate
    int 21 ; cf = error, al = status
; and then
    mov word [cs:callback_proc + 2], cs
    mov ax, 0xC207 ; setup callback
    les bx, [callback_proc]
    int 21 ; cf = error
; callback ptotype
mouse_callback:
  virtual at bp + 6
    .state dw ?
    .X     dw ?
    .Y     dw ?
    .flags dw ? ; always zero (reserved)
  end virtual
    push bp
    mov bp, sp

    leave
    retf
callback_proc dd mouse_callback and 0xFFFF