title: How to write a AT+CUSD ussd command to support maximum handsets
body: <p>I am facing an issue related to <code>AT+CUSD</code> command. On some Gsm modems, this command expects three parameters while on the others, it expects just two parameters. Moreover, different values of those parameters.</p>
  
  <p>I want to know that, <strong>how can I configure the Gsm modem so that this command can be executed in a uniform way</strong> on most Gsm modems.</p>
  
  <p>Forexample: On <strong>Nokia c6-01</strong>, the cusd command is executed successfully only in this way:</p>
  
  <pre><code>AT+CUSD=1,"*123#",15
  </code></pre>
  
  <p>Whereas on Sony Ericsson K750:</p>
  
  <pre><code>AT+CUSD=1,"*123#"
  </code></pre>
  
  <p>It gives an error if I give a third parameter.</p>