Sending USSD code with alphabetic characters

Question

In my android app, I am sending USSD codes (#144#73#) using below Intent :

String baseUssd = Uri.encode(\"#\") + \"144         


        

Answer 1

Meaning that the dialer transform this : #144#73MA#

to this #144#7362# : why ?

I will try to answer only the why part.

Intent.ACTION_CALL is handled by OutgoingCallBroadcaster class. If you look at processIntent() method, there is this piece of code (lines 438~448 as of this writing):

String number = PhoneNumberUtils.getNumberFromIntent(intent, this);
// Check the number, don't convert for sip uri
// TODO put uriNumber under PhoneNumberUtils
if (number != null) {
    if (!PhoneNumberUtils.isUriNumber(number)) {
        number = PhoneNumberUtils.convertKeypadLettersToDigits(number);
        number = PhoneNumberUtils.stripSeparators(number);
    }
} else {
    Log.w(TAG, "The number obtained from Intent is null.");
}

There PhoneNumberUtils.convertKeypadLettersToDigits() converts the letters into the equivalent numeric digits:

public static String convertKeypadLettersToDigits (String input)

Translates any alphabetic letters (i.e. [A-Za-z]) in the specified phone number into the equivalent numeric digits, according to the phone keypad letter mapping described in ITU E.161 and ISO/IEC 9995-8.

Returns
the input string, with alpha letters converted to numeric digits using the phone keypad letter mapping. For example, an input of "1-800-GOOG-411" will return "1-800-4664-411".

Hope this helps.