Call back security, also known as dial back security, is a security mechanism used to authenticate users over dialup lines. The way call back security works is the dialup user calls into the system and enters his username and password. The system then hangs up on the user and calls the user back at a …
Each GSM and UMTS mobile phone has a unique IMEI (International Mobile Equipment Identity) number. An IMEI number facilitates an important function – it easily identifies a mobile phone being used on a GSM (Global System for Mobile Communications) network. The IMEI is a useful tool to stop a stolen phone from accessing a network …
Cordless phones, also known as cordless telephones or portable telephones, are a smarter replacement for the regular telephones. Cordless phones make use of wireless radio waves to connect to their base station equipments, unlike the wired cord of a regular telephone. Because cordless handsets use radio linking with their base stations, they operate within specific …
The Global System for Mobile Communications (GSM) system is a widely deployed digital mobile telephony standard that is deployed throughout Europe and other locations around the globe. The GSM standard leverages a variant of TDMA (time division multiple access) and is the most deployed of the three competing legacy digital wireless technologies on the market …
Phone prefixes are the codes that tell the phone companies which state, city, or county a person is calling from. As more people move to an area the phone prefixes change and additional ones are added. Depending on the state, there may only be a few prefixes. Prefixes help to differentiate between each person's phone …
PCS (Personal Communications Service) is a set of standards. Most PCS standards are based on an existing standard. PCS is little more than the operation of these standards on the frequency bands of 1930-1990MHz for receiving and 1850-1910Mhz for transmitting. PCS StandardBase Standard PCS TDMA IS-136 PCS CDMA IS-95 PCS 1900 GSM PACS PHS cordless …
Loop start is a a signaling technique in which a party gets a dial tone by closing (shorting) a DC current loop. In a loop start signaling system, the electrical loop between your telephone and your central office (CO) is normally open. When you pick up the telephone handset, it causes a circuit to be …
When dealing with a wet phone, it is important to act quickly. Few phone companies offer a warranty on wet phones and have gone as far as to place a "wet strip" on the phone that changes colors when it has gotten wet. What this means is that the wet strip will allow the company …
Cell phone signal boosters (or cellular repeaters) are bidirectional amplifiers designed to boost the mobile phone reception using internal signal amplifiers, reception antennas and rebroadcast antennas. External antennas collect good cellular signal, and then it is transmitted to an amplifier, which retransmits the signal locally. This process results in much better signal. Rural areas often …
TTY/TDD stands for a group of telecommunication devices that make it easier for deaf and/or mute people to talk over telephone lines. TTY stands for telephone typewriter, teletypewriter or text phone. TDD stands for Telecommunications Device for the Deaf. Usually these devices are all categorized under TTY/TDD. Sometimes TTY means manual devices such as typewriters, …