initiate a phone call on android with special character #

I believe the problem is the that the # symbol has a special meaning in URIs, so you have to encode it using the Uri.encode() method like this:

    Intent out = new Intent();
    out.setAction(Intent.ACTION_DIAL);
    out.setData(Uri.parse("tel:" + Uri.encode("+12345#123")));
    startActivity(out);