IS-95 is a standard for CDMA (Code Division Multiple Access) Digital Cellular. Mobile Frequency Range Rx: 869-894; Tx: 824-849 Multiple Access Method CDMA/FDM Duplex Method FDD Number of Channels 20 (798 users per channel) Channel Spacing 1250kHz Modulation QPSK/OQPSK Channel Bit Rate 1.2288Mb How CDMA Works In a CDMA system, your encoded voice is digitized and divided into packets. These packets are tagged with "codes." The packets then mix with all of the other packets of traffic in the local CDMA network as they are routed towards their destination. The Read More

Long term evolution (LTE) is a project name that is given to the next generation of mobile phone speed otherwise known as 4G. Specifically, LTE is the last step that mobile phone companies have made to increase the speed and efficiency of their mobile phone devices. While LTE has been marketed as 4G, it doesn't quite comply with all the rules of IMT Advanced 4G requirements. Regardless, many companies across the world have announced that they are going to be pushing for 4G over the coming years starting in 2009. Read More

The BlackBerry OS is deployed on mobile devices used in 91 countries across more than 500 service operators. Research In Motion (RIM) developed the operating system since 1999, which allows mobile devices to act as both digital assistants and portable media players depending on the type of device purchased. A common task that arises for Blackberry owners is updating the Blackberry OS. How to Update the Blackberry OS Step 1 – Identify the Blackberry model by selecting the “Options” and “About” menu options. Annotate the device model number and software Read More

To connect Bluetooth devices, the most important to consider is that you have the right device to connect to the computer or cell phone. While most Bluetooth devices are able to sync with all different types of hardware, some of specific and therefore, before buying, make sure that what you are buying will work with your hardware. Once you've got the right Bluetooth device, connection is a very simple process. Connecting Bluetooth Devices to a Computer Go to your Hardware section on your computer and access the Bluetooth feature. Many Read More

A prepaid cell phone is one that allows users to pay in advance for their service without the commitment and penalties of a long term contract. While contract plans are still the most popular form of mobile phone service, prepaid cell phones have become very popular in recent years and have grown in use amidst rising contract prices. Most cell phone companies now provide prepaid cell phones and prepaid cell phones are even available in many convenience stores and gas stations. How It Works Prepaid cell phones are actually rather Read More

Code Division Multiple Access (CDMA) is a channel transmission standard that allows several transmitters to send information simultaneously over a single communication channel. This ensures that the available bandwidth is used in an optimized manner. It is a form of multiplexing and is used for wireless communication. Radio communication makes use of two resources: frequency and time. If individual frequencies are allocated part of the spectrum all within the band all of the time, the result is Frequency Division Multiple Access (FDMA). If the same frequency channel is shared by Read More

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 have problems with bad signal. Most service providers won’t make new towers in rural areas, because housing density is low. Cell phone signal boosters can solve this problem. Certain construction materials can block the signal. Read More

IS-54 and IS-136 are standards for TDMA American Digital Cellular. Mobile Frequency Range Rx: 869-894; Tx: 824-849 Multiple Access Method TDMA/FDM Duplex Method FDD Number of Channels 832 (3 users per channel) Channel Spacing 30Khz Modulation DQPSK Channel Bit Rate 48.6Kb IS-54 and IS-136: TDMA Security IS-54 and IS-136 use the CAVE (Cellular Authentication, Voice Privacy and Encryption) algorithm for authentication and the CMEA (Cellular Message Encryption Algorithm) for encryption. CAVE and CMEA are documented in Common Cryptographic Algorithms and Interface Specification for Common Cryptographic Algorithms. David Wagner, Bruce Schneier Read More

This "mosquito ringtone" is the original "secret ringtone." A secret ringtone is any ringtone which is recorded above 15Khz. Most adults are unable to hear frequencies above 15Khz due to age-related hearling loss known as presbycusis. Because of this, secret ringtones such as the mosquito ringtone can usually only be heard by people up to their mid twenties. This sound was originally developed by Howard Stapleton of Compound Security Systems as a way to prevent young people from loitering around businesses. That product was named the Mosquito, because the sound Read More

To understand what an unlocked cell phone is, it is important to first understand what a locked cell phone is. A locked cell phone is one that can only be used with one cellular service provider. In contrast, an unlocked cell phone can be used with any cellular service provider. When a cell phone is locked, it only recognizes a SIM (Subscriber Identification Module) card that the cellular service provider that the cell phone is locked to (a SIM card is a microchip that stores data and provides cellular service Read More