title: 8086 programming using TASM: pc to pc communication
body: <pre><code>.model small
  .stack 100
  .data
  .code
  
  mov ah,00h
  mov al,0e3h
  mov dx,00h
  int 14h
  
  back: nop
  
  l1: mov ah,03h
      mov dx,00h
      int 14h
  
      and ah,01h
      cmp ah,01h
      jne l1
  
      mov ah,02h
      mov dx,00h
      int 21h
  
  mov dl,al
  mov ah,02h
  int 21h
  
  jmb back
  mov ah,4ch
  int 21h
  
  end
  </code></pre>
  
  <p>This a pc to pc commnication receiver program.  I would like to know
  why it uses the <code>mov dx,00h</code> command and what <code>mov al,0e3h</code> means?</p>