this ael2 code:
macro ael-std-exten-ael( ext , dev ) {
        Dial(${dev}/${ext},20);
        switch(${DIALSTATUS}) {
        case BUSY:
                NoOp( sending to voicemail b${ext} , dev is ${dev} );
                VoiceMail(b${ext});
                break;
        default:
                NoOp( sending to voicemail u${ext}, dev is ${dev}  );
                VoiceMail(u${ext});
        };
        catch a {
                NoOp( caught a );
                VoiceMailMain(${ext});
                return;
        };
};


generates this dialplan:
[ Context 'macro-ael-std-exten-ael' created by 'pbx_ael' ]
  'a' =>            1. NoOp( caught a )                           [pbx_ael]
                    2. VoiceMailMain(${ext})                      [pbx_ael]
                    3. Goto(4)                                    [pbx_ael]
                    4. NoOp(End of Extension a)                   [pbx_ael]
  's' =>            1. Set(ext=${ARG1})                           [pbx_ael]
                    2. Set(dev=${ARG2})                           [pbx_ael]
                    3. Dial(${dev}/${ext}|20)                     [pbx_ael]
                    4. Goto(sw-55-${DIALSTATUS}|1)                [pbx_ael]
                    5. NoOp(Finish switch-ael-std-exten-ael-55)   [pbx_ael]
  'sw-55-BUSY' =>   1. NoOp( sending to voicemail b${ext} | dev is ${dev} ) [pbx_ael]
                    2. VoiceMail(b${ext})                         [pbx_ael]
                    3. Goto(s|5)                                  [pbx_ael]
  '_sw-55-.' =>     1. NoOp( sending to voicemail u${ext}| dev is ${dev}  ) [pbx_ael]
                    2. VoiceMail(u${ext})                         [pbx_ael]
                    3. Goto(s|5)                                  [pbx_ael]