e MSC to the SMSC and then to the originating SME. 20.4 Advanced Uses of SMS Beyond the obvious functions of paging service technicians and sending cute love notes, SMS has some interesting applications: Binary SMS messages can be used to configure or reconfigure cellular phones via OTAPA. If a subscriber calls in with a problem, the vendor's technician can reprogram and, in some cases, upgrade the user terminal over the air interface. Customer-service information, such as instructions or frequently asked question (FAQ) notes can be sent via SMS. There is an internetworking function between e-mail systems and SMS. This allows for SMS notification of new e-mail and even for forwarding of e-mails to the cellular telephone. SMS can interact with the Wireless Application Protocol (WAP), which provides a scaled- down World Wide Web interface for user terminals with limited screens, such as cellular telephones. WAP applications can give SMS users direct access to specially designed Web pages. Using WAP or other programming approaches, news items can be sent via SMS. SMS can transmit stock quotations. Recently, one wireless provider offered a promotion based on its ability to provide World Cup soccer scores in short messages. SMS also supports interaction between cellular telephones and other user devices through interfaces other than the air interface. It is possible to download SMS mes- sages from a cellular telephone into an appropriately designed personal computer or fax machine. However, this is one point where the otherwise excellent SMS specifica- tion was a little too vague. Some of these interfaces are implemented differently by dif- ferent vendors, and others are proprietary. This makes developing applications for these interfaces difficult. One interesting feature of SMS on GSM is that the SMS message can be stored ei- ther in the memory of the cellular telephone itself or in the memory of the personal identification card belonging to the subscriber. If the message is stored in the card, then it can be read o