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10. List of Abbreviations
• APN - Access Point Name – necessary for the GPRS service
• CLIP - Calling Line Identification Presentation
• CSD - Circuit Switched Data
• COM - PC serial port
• DTMF - Dual Tone Multifrequency - tone dialing
• EG - EasyGate
• FSK - Frequency Shift Keying
• FXO - an interface electrically identical with a standard telephone (opposite side =
FXS interface)
• FXS - a telephone interface allowing standard telephone connection (opposite
side = FXO interface)
• FW - Firmware - similar to SW, a term for the central microprocessor program
• GSM - Group Switched Mobile system - the present standard digital mobile telephone
network
• GPRS - General Packet Radio Service - high-speed data transmission for GSM
networks
• HW - Hardware - an electronic device, circuit, board, component, etc. in this context
• P(A)BX - Private (Automatic) Branch Exchange
• PC - Personal Computer (based on the IBM PC standard)
• PIN - Personal Identification Number - a SIM card securing password
• PUK - Personal Unblocking Key - a password used to unblock a blocked SIM card
after repeated wrong PIN entering
• RS-232C - a PC serial port standard
• SIM - Subscriber Identity Module - a chip-equipped module to be inserted in a
GSM device for identification
• SMS - Short Message Service, a term for the system and one unit (message)
• SW - Software
• TTL - Transistor-Transistor Logic - a standard digital technology defining voltage
for levels 0 and 1
• PSTN - Public Switched Telephone Network