An intercom is an intercom device.[1] It can be defined as an independent electronic communication system intended for limited or private dialogue. Intercoms can be portable although they are generally permanently installed in businesses, buildings and homes. They can incorporate connections with walkie talkies, pagers, telephones, cell phones or other telephone or data intercom systems, and they can also activate electronic or electromechanical devices, such as signal lights and locks.
Intercoms should not be confused with “doorman/entry systems,” where intercom is a system option.
Permanent and portable intercom systems
Traditional intercom systems are made up entirely of analog components, but many new functions are achieved thanks to new interfaces based on digital connections. Video signals can be interleaved with audio signals, digital intercom stations can be connected via Category 5 cables and can even use existing data networks as a means of interconnecting their parts remotely.
Many schools and office buildings now use audio/video systems to identify users attempting to access a locked building and can be interfaced to the access control system.
Intercom systems can be found on many types of vehicles, including trains, ships, aircraft, and armored fighting vehicles.
Portable systems are commonly used by event production teams and professional sports teams; performing arts centers such as theaters and concert halls often have a combination of fixed and portable intercom elements. In motorsport competition, on the tracks, they usually have portable and permanent intercom stations mounted at critical points, this to be used by officials, technicians and doctors in case of an emergency. These systems are made up of two types, analog and digital.
Connection types
Wired intercoms-
While each line of intercom products is different, most analog intercom systems have a lot in common. Voice signals of approximately one or two volts are carried to the top of a 12, 30 or 48 volt direct current voltage line using a pair of conductors. Light signal indications between stations can be achieved by using additional conductors or can be carried on the primary voice pair via tone frequencies sent above or below the speech frequency range. Multiple channels of simultaneous conversations can be carried over additional conductors within a cable or by frequency or time division multiplexing in the analog domain. Multiple channels can be easily transported by packet switching digital intercom signals.
Intercom and video intercom
Introduction
An intercom is an intercom device.[1] It can be defined as an independent electronic communication system intended for limited or private dialogue. Intercoms can be portable although they are generally permanently installed in businesses, buildings and homes. They can incorporate connections with walkie talkies, pagers, telephones, cell phones or other telephone or data intercom systems, and they can also activate electronic or electromechanical devices, such as signal lights and locks.
Intercoms should not be confused with “doorman/entry systems,” where intercom is a system option.
Permanent and portable intercom systems
Traditional intercom systems are made up entirely of analog components, but many new functions are achieved thanks to new interfaces based on digital connections. Video signals can be interleaved with audio signals, digital intercom stations can be connected via Category 5 cables and can even use existing data networks as a means of interconnecting their parts remotely.
Many schools and office buildings now use audio/video systems to identify users attempting to access a locked building and can be interfaced to the access control system.
Intercom systems can be found on many types of vehicles, including trains, ships, aircraft, and armored fighting vehicles.
Portable systems are commonly used by event production teams and professional sports teams; performing arts centers such as theaters and concert halls often have a combination of fixed and portable intercom elements. In motorsport competition, on the tracks, they usually have portable and permanent intercom stations mounted at critical points, this to be used by officials, technicians and doctors in case of an emergency. These systems are made up of two types, analog and digital.
Connection types
Wired intercoms-
Portable intercoms are connected primarily using common shielded, twisted-pair microphone wiring with 3-pin XLR connectors. Construction and vehicle intercoms are connected in a similar way with shielded cables often containing more than one twisted pair.
Digital intercoms use Category 5 cable and transmit information back and forth in data packets using the Internet Protocol architecture.
Intercoms using two-wire radio transmission-
They are intercom systems used in television stations and mobile units, such as those seen at sporting or entertainment events. There are essentially two types of intercoms used in the world of television:
Two-wire" or four-wire" matrix systems). At first, television stations simply built their own communication systems with old telephone equipment. However, today there are several manufacturers that offer exclusive systems. From the late 1970s to the mid-90s two-wire systems were the most popular, mainly due to the technology that was available at the time. The two channel variety used a 32 volt impedance in generating the central power supply to drive the external stations or band packs. This type of format allowed the two channels to operate on a standard microphone cable, a feature highly desired by broadcasters. These systems are very robust and easy to design, maintain and operate, but had limited capacity and flexibility since they were usually hardwired. A typical user of the system could not choose who to talk to, he would communicate with the same person or group of people until the system was manually reconfigured to allow communication with a different group of people. Two-wire routers or source mapping panels were implemented to allow rapid re-routing. This reconfiguration was usually handled in a central office, because the voltage was used in the power circuit of the external user stations, as well as for communication, so it usually made a pop when the channels were changed. Although you could change the channel on the fly, it was generally not advisable to do so in the middle of a production, as the noise would distract the rest of the crew.
Intercoms using four-wire radio broadcasting
Four-wire technology in the mid-90s began to gain more importance as the technology became increasingly cheaper and the product smaller. Four-wire technology had been around for a while, but it was very expensive to implement, usually requiring a large studio space, so it was only used on very large stations or television networks.
Telephone intercom "Central Telefónica"
Some telephone equipment was influenced by the functions and benefits of intercoms; these allowed conversations between devices of similar make and model, incorporating the flexibility of using telephone devices. Some examples include models from Ericsson, Siemens, Alcatel, AT&T, Panasonic, TMC and more recently Skyphone[2] in Latin America.
A single device can offer the functionality of intercommunicating with multiple telephone devices and incorporating telephone lines; there are different brands and models.
The installation effort is minimal, and it is not vulnerable to radio interference and security problems of wireless systems. Intercommunication is achieved in all environments with the possibility of transferring telephone calls to the required user, multiple calling is achieved by ringing a distinctive ring on all telephones, then anyone picks up the call. If while the user is in a conversation, a second call comes in, he or she will hear a warning tone in the handset.
For intercoms in buildings and condominiums, many technicians use telephone exchanges and a special intercom at the entrance of the building with a keyboard, this keyboard is the one that allows communication with any apartment in the building. This application has been well received, since the owners obtain internal communication, something that they did not have with conventional intercoms.
While each line of intercom products is different, most analog intercom systems have a lot in common. Voice signals of approximately one or two volts are carried to the top of a 12, 30 or 48 volt direct current voltage line using a pair of conductors. Light signal indications between stations can be achieved by using additional conductors or can be carried on the primary voice pair via tone frequencies sent above or below the speech frequency range. Multiple channels of simultaneous conversations can be carried over additional conductors within a cable or by frequency or time division multiplexing in the analog domain. Multiple channels can be easily transported by packet switching digital intercom signals.
Portable intercoms are connected primarily using common shielded, twisted-pair microphone wiring with 3-pin XLR connectors. Construction and vehicle intercoms are connected in a similar way with shielded cables often containing more than one twisted pair.
Digital intercoms use Category 5 cable and transmit information back and forth in data packets using the Internet Protocol architecture.
Intercoms using two-wire radio transmission-
They are intercom systems used in television stations and mobile units, such as those seen at sporting or entertainment events. There are essentially two types of intercoms used in the world of television:
Two-wire" or four-wire" matrix systems). At first, television stations simply built their own communication systems with old telephone equipment. However, today there are several manufacturers that offer exclusive systems. From the late 1970s to the mid-90s two-wire systems were the most popular, mainly due to the technology that was available at the time. The two channel variety used a 32 volt impedance in generating the central power supply to drive the external stations or band packs. This type of format allowed the two channels to operate on a standard microphone cable, a feature highly desired by broadcasters. These systems are very robust and easy to design, maintain and operate, but had limited capacity and flexibility since they were usually hardwired. A typical user of the system could not choose who to talk to, he would communicate with the same person or group of people until the system was manually reconfigured to allow communication with a different group of people. Two-wire routers or source mapping panels were implemented to allow rapid re-routing. This reconfiguration was usually handled in a central office, because the voltage was used in the power circuit of the external user stations, as well as for communication, so it usually made a pop when the channels were changed. Although you could change the channel on the fly, it was generally not advisable to do so in the middle of a production, as the noise would distract the rest of the crew.
Intercoms using four-wire radio broadcasting
Four-wire technology in the mid-90s began to gain more importance as the technology became increasingly cheaper and the product smaller. Four-wire technology had been around for a while, but it was very expensive to implement, usually requiring a large studio space, so it was only used on very large stations or television networks.
Telephone intercom "Central Telefónica"
Some telephone equipment was influenced by the functions and benefits of intercoms; these allowed conversations between devices of similar make and model, incorporating the flexibility of using telephone devices. Some examples include models from Ericsson, Siemens, Alcatel, AT&T, Panasonic, TMC and more recently Skyphone[2] in Latin America.
A single device can offer the functionality of intercommunicating with multiple telephone devices and incorporating telephone lines; there are different brands and models.
The installation effort is minimal, and it is not vulnerable to radio interference and security problems of wireless systems. Intercommunication is achieved in all environments with the possibility of transferring telephone calls to the required user, multiple calling is achieved by ringing a distinctive ring on all telephones, then anyone picks up the call. If while the user is in a conversation, a second call comes in, he or she will hear a warning tone in the handset.
For intercoms in buildings and condominiums, many technicians use telephone exchanges and a special intercom at the entrance of the building with a keyboard, this keyboard is the one that allows communication with any apartment in the building. This application has been well received, since the owners obtain internal communication, something that they did not have with conventional intercoms.