DTMF tones, or Dual-Tone Multi-Frequency signaling, are audible tones that are used by touch-tone telephones to identify which number key was pushed by the operator. DTMF tones have been used since 1963 and are used by all standard touch-tone telephones in the United States as well as in many other countries around the world. DTMF tones can be heard while the operator enters each digit, but must be decoded by a DTMF decoder at the telephone company’s switching center before a call can be completed.   How DTMF Tones Work Read More

Telephone wires are easy to work with and very safe due to the low voltages involved. The most complex part of installing telephone wires is complying with the defined standards. When installing additional telephone wires into an existing facility, it is usually best to determine which telephone wiring standard is currently in use and conform to that standard. When installing telephone wiring into a new facility, EIA/TIA T586A is the standard to utilize. How the Wire Gets into a Residence Historically, telephone companies ran telephone wires above ground with telephone Read More

Telephone voltage is actually related to the physical distance at which you can operate the telephone. If the voltage is high, it can signal to great distance. However, higher voltage carries certain risks. 48 V is a compromise between distance and safety. 50-52 V is used in central office common batteries, but designations and documents still use the nominal voltage. In the 20th century, some rural areas in theU.S. used range extenders. They operated at 130 V. The goal was to achieve reliable signaling. Some of the systems used in Read More

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 closed — creating a loop. Loop start signaling is normally used POTS (Plain Old Telephone System) lines and key-switch systems. The most common alternative to loop start is ground start. Advantages and Disadvantages Unlike ground Read More

For many small, medium and large businesses outsourcing a call center is an excellent way to generate sales and help current customers with tech support and customer support issues. While some larger companies have the money, time and resources to put in place their own call center, most smaller and mid sized businesses opt for a streamline approach to call centers and choose to outsource their call center needs. Here are some tips on how to outsource a call center. If you are looking to outsource a call center, your Read More

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 your mobile telephone to generate a random ESN (Electronic Serial Number) and a random MIN (Mobile Identification Number) from an Area Code served by the carrier you configured into your mobile telephone in the first Read More

A ringtone is a custom sound that plays when some mobile phones receive an incoming call. Early cell phones had very boring rings, just like standard landline telephones. When a dozen people were in a meeting and one of their cell phones rang, it took some time to sort out whose cell phone was ringing! Ringtones allow each of us to give our cell phones a bit of personality, while at the same time they help us to sort out our incoming calls from everyone elses incoming calls. Ringtone Formats Read More

Cell phone tracking is used to track the current position of a cell phone. An active call is not required to track the current position of the cell phone, but the cell phone must be turned on for a successful tracking. GSM localization uses multilateration to establish the position of GSM cell phones, generally with the objective to trace the user. GSM localization is then done by triangulation to locate the user/cell phone, on the basis of the strength of the signals. Triangulation is the process of finding one’s position Read More

RBOC (The Regional Bell Operating Companies) were created as the result of a legal dispute between the US Justice Department and the AT & T Corporation. In 1984, the American Telephone & Telegraph Company split its local operations into 7 autonomous RBOCs that became known as “Baby Bells”. In the beginning, these companies were called RHCs (Regional Holding Companies). After 1984, one part of the AT & T was split to form Bellcore that served as a standard body for other Baby Bells. The Science Applications International Corp. acquired Bellcore Read More

Loops are a pair of phone numbers, usually consecutive, like 836-9998 and 836-9999. They are used by the phone company for testing. What good do loops do us? Well, they are cool in a few ways. Here is a simple use of loops. Each loop has two ends, a 'high' end, and a 'low' end. One end gives a (usually) constant, loud tone when it is called. The other end is silent. Loops don't usually ring either. When BOTH ends are called, the people that called each end can talk Read More