SMS stand for (Short Message Service) which is used for commonly as "text messaging" is a service for sending short messages of up to 160 characters in mobile phones devices, including cellular phones, smart phones and PDAs . SMS is same as paging. However, SMS messages do not require the mobile phone to be active and with in range and will be held for a number of days until the phone is active and within range. SMS messages are transmitted within the same Cell phone or to anyone with roaming services capability. They can also be sent to digital phones.