<page xmlns="http://projectmallard.org/1.0/"
      type="guide"
      id="usage-ussd">

    <info>
        <link type="guide" xref="index#usage"/>
        <revision pkgversion="0.0.19" version="0.1" date="2017-11-11" status="incomplete"/>
        <desc>
            Use <app>Modem Manager GUI</app> for send USSD codes and receive the answers.
        </desc>
        <credit type="author">
            <name>Mario Blättermann</name>
            <email>mario.blaettermann@gmail.com</email>
        </credit>
        <credit type="author">
            <name>Alex</name>
            <email>alex@linuxonly.ru</email>
        </credit>
        <license>
            <p>Creative Commons Share Alike 3.0</p>
        </license>
    </info>
    
    <title>USSD codes</title>
    
    <p>
    <app>Modem Manager GUI</app> is able to send USSD codes. These codes are controlling
    some network functions, for example the visibility of your phone number when sending a SMS.
    </p>
    
    <p>
    To use the USSD functions, click on the <gui style="button">USSD</gui> button
    in the toolbar.
    </p>
    
    <figure>
        <title>USSD window of <app>Modem Manager GUI</app>.</title>
        <media type="image" mime="image/png" src="figures/ussd-window.png"/>
    </figure>
    
    <p>
    In the text entry on top of the window, the code <cmd>*100#</cmd> is already displayed.
    This code is the usual one for requesting the balance for a prepaid card. If you like
    to send another code, click on the <gui style="button">Edit</gui> button on the right.
    </p>
    
    <p>
    <app>Modem Manager GUI</app> supports interactive USSD sessions, so pay attention to hints
    displayed under USSD answers. You can send USSD responses using text entry for USSD commands. If
    you'll send new USSD command while USSD session is active, this session will be closed automatically.
    </p>
    
    <note style="hint">
        <p>
        If you use Huawei device and get unreadable USSD answers, you can try to click on the
        <gui style="button">Edit</gui> button and toggle the <gui style="button">Change message encoding</gui>
        button in the toolbar of opened window.
        </p>
    </note>
    
    <note style="hint">
        <p>
        USSD codes are only available in networks which use the
        <link href="http://en.wikipedia.org/wiki/3rd_Generation_Partnership_Project">3GPP standards</link>.
        </p>
    </note>
    
    <p>
    You can use such codes for many purposes: change plan, request balance, block number, etc.
    </p> 
         
</page>
