Обратная косая черта - быстрый ответ:
>>> '(+CMGL: 2,"REC READ","DD-Etopup",,"11/11/04,12:48:51+22" Hye! How\'s it going?)'
'(+CMGL: 2,"REC READ","DD-Etopup",,"11/11/04,12:48:51+22" Hye! How\'s it going?)'
>>> a = '(+CMGL: 2,"REC READ","DD-Etopup",,"11/11/04,12:48:51+22" Hye! How\'s it going?)'
>>> a.split(',')
['(+CMGL: 2', '"REC READ"', '"DD-Etopup"', '', '"11/11/04', '12:48:51+22" Hye! How\'s it going?)']
>>> a.split(',')[5]
'12:48:51+22" Hye! How\'s it going?)'
>>> len(a.split(',')[5])
34