|
Intercom Telephone
An intercom telephone is a special kind of telephone that controls an intercom system. Intercom telephones can be found in residential, commercial, and educational settings. For an example, a school is an environment that displays all the capabilities of an intercom telephone. Using an intercom telephone, administrators can make announcements over loudspeakers that are heard by the entire building, but they can also call a specific classroom's intercom by dialing the room number of that classroom. Intercom telephones can be interfaced with a building's access control system. See also * Courtesy telephone * Speaking tube A speaking tube or voicepipe is a device based on two cones connected by an air pipe through which speech can be transmitted over an extended distance. Use of pipes was suggested by Francis Bacon in the ''New Atlantis'' (1672). The usage for tel ... References Telecommunications equipment {{Telecommunications-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone
A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals that are transmitted via cables and other communication channels to another telephone which reproduces the sound to the receiving user. The term is derived from el, τῆλε (''tēle'', ''far'') and φωνή (''phōnē'', ''voice''), together meaning ''distant voice''. A common short form of the term is ''phone'', which came into use early in the telephone's history. In 1876, 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 at a second device. This instrument was further developed by many others, and became rapidly indispensable in business, government, and in households. The essential elements of a telephone are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intercom
An intercom, also called an intercommunication device, intercommunicator, or interphone, is a stand-alone voice communications system for use within a building or small collection of buildings which functions independently of the public telephone network. Intercoms are generally mounted permanently in buildings and vehicles. Intercoms can incorporate connections to public address loudspeaker systems, walkie talkies, telephones, and other intercom systems. Some intercom systems incorporate control of devices such as signal lights and door latches. Intercoms are used on a wide variety of properties; from houses that only require one connection between a resident and the property's entrance to multi-unit apartments that require intercom hardware to be installed in every individual apartment. Some are equipped with video and its wiring (electrical installation) can be connected to the outside with a few pairs (4-6 pairs) while controlling an electric strike. The latest generations a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
School
A school is an educational institution designed to provide learning spaces and learning environments for the teaching of students under the direction of teachers. Most countries have systems of formal education, which is sometimes compulsory. In these systems, students progress through a series of schools. The names for these schools vary by country (discussed in the '' Regional terms'' section below) but generally include primary school for young children and secondary school for teenagers who have completed primary education. An institution where higher education is taught is commonly called a university college or university. In addition to these core schools, students in a given country may also attend schools before and after primary (elementary in the U.S.) and secondary (middle school in the U.S.) education. Kindergarten or preschool provide some schooling to very young children (typically ages 3–5). University, vocational school, college or seminary may be avail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loudspeakers
A loudspeaker (commonly referred to as a speaker or speaker driver) is an Acoustical engineering#Electroacoustics, electroacoustic transducer that converts an electrical audio signal into a corresponding sound. A ''speaker system'', also often simply referred to as a "speaker" or "loudspeaker", comprises one or more such speaker ''drivers'', an enclosure, and electrical connections possibly including a Audio crossover, crossover network. The speaker driver can be viewed as a linear motor attached to a Diaphragm (acoustics), diaphragm which couples that motor's movement to motion of air, that is, sound. An audio signal, typically from a microphone, recording, or radio broadcast, is amplified electronically to a power level capable of driving that motor in order to reproduce the sound corresponding to the original unamplified electronic signal. This is thus the opposite function to the microphone; indeed the ''dynamic speaker'' driver, by far the most common type, is a linear mot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Classroom
A classroom or schoolroom is a learning space in which both children and adults learn. Classrooms are found in educational institutions of all kinds, ranging from preschools to universities, and may also be found in other places where education or training is provided, such as corporations and religious and humanitarian organizations. The classroom provides a space where learning can take place uninterrupted by outside distractions. Types of classroom In the United States In elementary schools (from Kindergarten through 5th grade), classrooms can have a whole group of 18 to 30 students (in some cases these numbers may differ) and one, two, or even three teachers. When there are two teachers in a classroom, one is the lead teacher and the other one is the associate. Or the second teacher might be a special education teacher. There may be a third teacher in the back watching and taking notes. In lower elementary the classrooms are set up slightly different from upper elementar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Access Control
In the fields of physical security and information security, access control (AC) is the selective restriction of access to a place or other resource, while access management describes the process. The act of ''accessing'' may mean consuming, entering, or using. Permission to access a resource is called ''authorization''. Locks and login credentials are two analogous mechanisms of access control. Physical security Geographical access control may be enforced by personnel (e.g. border guard, bouncer, ticket checker), or with a device such as a turnstile. There may be fences to avoid circumventing this access control. An alternative of access control in the strict sense (physically controlling access itself) is a system of checking authorized presence, see e.g. Ticket controller (transportation). A variant is exit control, e.g. of a shop (checkout) or a country. The term access control refers to the practice of restricting entrance to a property, a building, or a room to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Courtesy Telephone
A courtesy telephone is a telephone located in airport terminals, large train stations, hotel lobbies, and other places where many travellers are expected, which is used to relay messages to a specific person. It is typically used in connection with a public address system announcement of the style "Gwen Cooper, please pick up the nearest white courtesy telephone." Courtesy telephones may have a distinctive color, which is traditionally white in US airports, and most have no dialing capabilities but rather are simple ringdown stations to reach an operator or other fixed number. Some double as emergency telephones, having buttons by which a user can distinguish between emergency use and inquiry. Customers can use a courtesy phone to seek information, such as where to find further transport or a person trying to meet them. Some courtesy phones provide a direct line to a number of advertised businesses, such as motels or taxis. They may be located near baggage claim, ticketing areas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speaking Tube
A speaking tube or voicepipe is a device based on two cones connected by an air pipe through which speech can be transmitted over an extended distance. Use of pipes was suggested by Francis Bacon in the ''New Atlantis'' (1672). The usage for telecommunications was experimented and proposed for administrative communications in 1782 by the French monk Dom Gauthey in a memorandum communicated to the Académie des Sciences. Dom Gauthey launched a subscription supported by Benjamin Franklin and other French scientists to finance further experiments, but was not able to raise enough money to go ahead. The British utilitarist philosopher Jeremy Bentham proposed the inclusion of "conversation tubes" in the architecture of his Panopticon (1787, 1791, 1811) and then as a means of military telecommunication (1793) and at the end as a necessary equipment in the architecture of ministries (1825). While its most common use was in intra-ship communications, the principle was also used in affl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_(14569859438).jpg "Click for more on -> Intercom")
