an extended version of the Hayes command set. The extensions were standardised as part of the GSM Standards and extended as part of the 3GPP standards process. The connection between the terminal equipment and the transceiver can be realized with a serial cable (e.g., USB), a Bluetooth link, an infrared link, etc. Common AT commands include AT+CMGS (send message), AT+CMSS (send message from storage), AT+CMGL (list messages) and AT+CMGR (read message). However, not all modern devices support receiving of messages if the message storage (for instance the device's internal memory) is not accessible using AT commands. Premium-rated short messages Short messages may be used normally to provide premium rate services to subscribers of a telephone network. Mobile-terminated short messages can be used to deliver digital content such as news alerts, financial information, logos, and ring tones. The first premium-rate media content delivered via the SMS system was the world's first paid downloadable ringing tones, as commercially launched by Saunalahti (later Jippii Group, now part of Elisa Group), in 1998. Initially, only Nokia branded phones could handle them. By 2002 the ringtone business globally had exceeded $1 billion of service revenues, and nearly US$5 billion by 2008. Today, they are also used to pay smaller payments online—for example, for file-sharing services, in mobile application stores, or VIP section entrance. Outside the online world, one can buy a bus ticket or beverages from ATM, pay a parking ticket, order a store catalog or some goods (e.g., discount movie DVDs), make a donation to charity, and much more. The Value-added service provider (VASP) providing the content submits the message to the mobile operator's SMSC(s) using a TCP/IP protocol such as the short message peer-to-peer protocol (SMPP) or the External Machine Interface (EMI). The SMSC delivers the text using the normal Mobile Terminated delivery procedure. The subscribers are charged extra for receiving this premium content; the revenue is typically divided between the mobile network operator and the VASP either through revenue share or a fixed transport fee. Submission to the SMSC is usually handled by a third party. Mobile-originated short messages may also be used in a premium-rated manner for services such as televoting. In this case, the VASP providing the service obtains a short code from the telephone network operator, and subscribers send texts to that number. The payouts to the carriers vary by carrier; percentages paid are greatest on the lowest-priced premium