
Voice over IP at UCSB
... and synonymous with VoIP are IP telephony, Internet telephony, voice over broadband (VoBB), broadband telephony, and broadband phone. Internet telephony refers to communications services — voice, facsimile, and/or voice-messaging applications — that are transported via the Internet, rather than th ...
... and synonymous with VoIP are IP telephony, Internet telephony, voice over broadband (VoBB), broadband telephony, and broadband phone. Internet telephony refers to communications services — voice, facsimile, and/or voice-messaging applications — that are transported via the Internet, rather than th ...
Lecture_2012_1
... Flashing light and ringing devices to alert the called party of incoming call Called party information to operator to establish calls ...
... Flashing light and ringing devices to alert the called party of incoming call Called party information to operator to establish calls ...
FM 24-24 Chapter 1 Telephone Equipment Section I. Telephones
... The digital nonsecure voice terminal (DNVT) TA-954/TT is a four-wire terminal contained in a ruggedized case, which transmits and receives conditioned diphase-modulated digitized voice and loop signaling information at 16 or 32 kb/s. The DNVT has a 16-key push button keyboard, receiver and ring volu ...
... The digital nonsecure voice terminal (DNVT) TA-954/TT is a four-wire terminal contained in a ruggedized case, which transmits and receives conditioned diphase-modulated digitized voice and loop signaling information at 16 or 32 kb/s. The DNVT has a 16-key push button keyboard, receiver and ring volu ...
REMOTE CONTROLLED SMARTHOME OVER PSTN
... DTMF - Dual Tone Multi Frequency. With these tones are transmitted information from the user to the telephone PBX when the user wants to make a phone call, so the number you wish to call is transmitted digit by digit to PBX as specific signals for each key. These tones are signals that are included ...
... DTMF - Dual Tone Multi Frequency. With these tones are transmitted information from the user to the telephone PBX when the user wants to make a phone call, so the number you wish to call is transmitted digit by digit to PBX as specific signals for each key. These tones are signals that are included ...
GND GND GND
... When the LO C receives the customer number 1100, then the same process is repeated as described earlier for the call between 5000 and 4422 in the 455 Office. ...
... When the LO C receives the customer number 1100, then the same process is repeated as described earlier for the call between 5000 and 4422 in the 455 Office. ...
Telecommunication
... into pulses of light TAT 9 fiber optic cable can carry more than 75,000 telephone conversation at a time ...
... into pulses of light TAT 9 fiber optic cable can carry more than 75,000 telephone conversation at a time ...
Communications Networks: Fundamental Concepts and Key
... The caller sends this number by pushing the keys on the telephone set. Each key generates a pair of tones that specify a number. (In the older phone sets the user dials a number which in turn generates a corresponding number of pulses.) ...
... The caller sends this number by pushing the keys on the telephone set. Each key generates a pair of tones that specify a number. (In the older phone sets the user dials a number which in turn generates a corresponding number of pulses.) ...
Review PSTN
... 5. What is the typical a.c talking current? _________________ 6. What is the typical d.c loop current? _____________________ 7. The characteristics of #26 AWG Pulp telephone cable at 2kHz are as shown below. R = 440 Ohms /km, ...
... 5. What is the typical a.c talking current? _________________ 6. What is the typical d.c loop current? _____________________ 7. The characteristics of #26 AWG Pulp telephone cable at 2kHz are as shown below. R = 440 Ohms /km, ...
Telephone

A telephone, or phone, is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals suitable for transmission via cables or other transmission media over long distances, and replays such signals simultaneously in audible form to its user.In 1876, Scottish emigrant Alexander Graham Bell was the first to be granted a United States patent for a device that produced clearly intelligible replication of the human voice. This instrument was further developed by many others. The telephone was the first device in history that enabled people to talk directly with each other across large distances. Telephones rapidly became indispensable to businesses, government, and households, and are today some of the most widely used small appliances.The essential elements of a telephone are a microphone (transmitter) to speak into and an earphone (receiver) which reproduces the voice in a distant location. In addition, most telephones contain a ringer which produces a sound to announce an incoming telephone call, and a dial used to enter a telephone number when initiating a call to another telephone. Until approximately the 1970s most telephones used a rotary dial, which was superseded by the modern DTMF push-button dial, first introduced to the public by AT&T in 1963. The receiver and transmitter are usually built into a handset which is held up to the ear and mouth during conversation. The dial may be located either on the handset, or on a base unit to which the handset is connected. The transmitter converts the sound waves to electrical signals which are sent through the telephone network to the receiving phone. The receiving telephone converts the signals into audible sound in the receiver, or sometimes a loudspeaker. Telephones permit duplex communication, meaning they allow the people on both ends to talk simultaneously.A landline telephone is connected by a pair of wires to the telephone network, while a mobile phone, such as a cellular phone (which first became commercially available in the early 1980s) is portable and communicates with the telephone network by radio transmissions. The public switched telephone network has many switching centers that interconnect telephones around the world for direct communication with each other. Each telephone line has an identifying telephone number. To initiate a telephone call the user enters the destination telephone's number into a dial or numeric keypad on the phone. Graphic symbols used to designate telephone service or phone-related information in print, signage, and other media include ℡ (U+2121), ☎ (U+260E), ☏ (U+260F), ✆ (U+2706), and ⌕ (U+2315).Although originally designed for simple voice communications, convergence has enabled most modern cell phones to have many additional capabilities. They may be able to record spoken messages, send and receive text messages, take and display photographs or video, play music or games, surf the Internet, do road navigation or immerse the user in virtual reality. Since 1999, the trend for mobile phones is smartphones that integrate all mobile communication and computing needs.