| Word | Description |
| SIM | Subscriber Identity Module (SIM) - A card inserted into a GSM/TDMA or GSM-only handset containing subscriber-related data. The card contains 18 digits for GSM markets and 20 digits for TDMA markets. |
| SMS | Short Message Service (SMS) - The transmission of short alphanumeric text-messages to and from a mobile phone, fax machine and/or IP address. Messages must be no longer than 160 alphanumeric characters and contain no images or graphics. Once a message is sent, it is received by a Short Message Service Center (SMSC), which must then get it to the appropriate mobile device. |
| WAP | Wireless Application Protocol (WAP) - An open standard for communication between handsets and the Internet. WAP is a wireless communications environment for delivering web data to wireless terminals with minimal screen display. An initiative started by Unwired Planet, Motorola, Nokia and Ericsson to develop a standard for wireless content delivery on the next generation of mobile communicators. WAP strips all but graphics for display on small screens, such as mobile phones. A mini-browser is an integral part of WAP enabled phones. WAP enabled phones first appeared in Europe at the end of 1999. |