title: Android as SIP to GSM gateway
body: <p>Soon I could use a SIP to GSM gateway, because I'll need to make phone calls from Germany to a mobile phone in Czech Republik. Hence, I thought about implementing one.</p>
  
  <p>Now, the questions are:</p>
  
  <ul>
  <li>Does such a solution already exist (for a reasonable price)?</li>
  <li>Is it possible to redirect a (voice) stream to a GSM connection with the available Android APIs (SDK or NDK)?</li>
  </ul>
  
  <p>Ideas, suggestions, comments are highly welcome.</p>