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    • AMPS (EIA/TIA-553) and NAMPS (IS-91)

      AMPS (EIA/TIA-553) and NAMPS (IS-91)

      Mobile Frequency Range Rx: 869-894; Tx 824-849 Multiple Access Method FDM Duplex Method FDD Number of Channels 832 Channel Spacing 30kHz Modulation FM AMPS AMPS (Advanced Mobile Phone Service) was the first cellular mobile system in the United States. AMPS operates as an analog system using 30 kHz wide channels. NAMPS AMPS was later enhanced

    • 15 Ways to Improve Your Phone’s Battery Life

      15 Ways to Improve Your Phone’s Battery Life

      Although mobile phones have become almost ubiquitous in modern culture, device manufacturers have yet to solve the problem of significantly improving the battery life of mobile phones significantly. As a result, consumers must seek out methods to manage the overall application and program usage on their cell phones in order to improve the overall life

    • Cell Phone Frequencies

      Cell Phone Frequencies

      Cell phone frequencies are the frequency ranges within the Ultra High Frequency (UHF) band that are designated for cell phone use. Bluetooth devices, wireless networks, and television signals also use this frequency band. Although cellular phone systems divide cities and geographic areas into smaller cells of coverage, it allows for a fair amount of frequency

    • How Mobile Phones Are Dangerous to Health

      How Mobile Phones Are Dangerous to Health

      Since the number of cell phone users has continued to increase to more than six billion subscriptions at the turn of the decade, a common question that continues to get asked is how dangerous are mobile phones to one’s health? This question has continued to be asked over the past several decades since mobile phones

    • Pay as You Go Cell Phones

      Pay as You Go Cell Phones

      Sometimes called pre paid or prepay cell phone plans, Pay as You Go Cell Phones are usually used in specific types of mobile phone calling plans. Unlike standard mobile phone calling plans that charge a set monthly fee for a specific amount of calls, pay as you go cell phone calling plans only require the

    • How to Unlock a GoPhone

      How to Unlock a GoPhone

      GoPhone is the trademark used by AT&T/Cingular to market their pay as you go cell phones. Most customers will eventually want to switch to a more normal post-pay cell phone plan, and many of them will want to take their cell phones with them. Unfortunately, the GoPhones are "subsidy locked." This means that the GoPhones

    • NAM: Number Assignment Module

      NAM: Number Assignment Module

      The NAM (Number Assignment Module) is the EPROM (Erasable Programmable Read-Only Memory) in a mobile telephone which holds information such as the MIN (or MDN) and SIDH.  The data fields stored in a phone’s NAM vary between the various mobile telephone specifications, such as AMPS/NAMPS, GSM, PCS, CMDA.  In modern networks, NAMs can be reprogrammed

    • TIMSI

      TIMSI

      A TIMSI, or Temporary International Mobile Subscriber Identity, number is a random number that is created from a telecommunications subscriber’s IMSI number in order to provide additional security. While an IMSI is unique to each subscriber and is a permanent number that can be used to track a subscriber or interfere with his/her services, a

    • Tumbling

      Tumbling

      Tumbling exploits a weakness in the AMPS/NAMPS roaming system. In tumbling, you first configure the SIDH in your mobile telephone to pretend to be from another cellular carrier. If you are in Colorado, for example, you would configure your mobile telephone as if it were subscribed to a cellular carrier in Texas. Next, you modify

    • iDEN (Integrated Digital Enhanced Network)

      iDEN (Integrated Digital Enhanced Network)

      An IDEN, or Integrated Dispatch Enhanced Network, is a radio service provided by some mobile telephones that allows subscribers to talk to nearby subscribers who have similar phones without dialing their individual numbers. IDENs are often provided as a free service on modern mobile phones, such as Nextel, or as a premium service that can

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