Control means of an exchange comprising connection means for accommodating a telephone and the control means for controlling the accommodated telephone, receives a dial signal from the telephone without causing the telephone to respond to an incoming call when the telephone that is performing incoming call ringing is hooked off, causes the hooked-off telephone to respond to the incoming call when the received dial signal is a first dial signal, and causes the telephone as a call source to make a call without causing the hooked-off telephone to respond to the incoming call when the received dial signal is a second dial signal. Thereby, it is possible to make a call even during incoming call ringing.

Control means of an exchange comprising connection means for accommodating a telephone and the control means for controlling the accommodated telephone, receives a dial signal from the telephone without causing the telephone to respond to an incoming call when the telephone that is performing incoming call ringing is hooked off, causes the hooked-off telephone to respond to the incoming call when the received dial signal is a first dial signal, and causes the telephone as a call source to make a call without causing the hooked-off telephone to respond to the incoming call when the received dial signal is a second dial signal. Thereby, it is possible to make a call even during incoming call ringing.

In an intercom system to be used in an apartment complex configured by residential buildings and a centralized building that can communicate with the residential buildings, the residential buildings includes: residential room master devices disposed in residential rooms, collective entrance devices which can communicate with the residential room master devices; and a building controller. The building controller has: a building controller ID that, when the centralized building is called by one of the residential room master devices via the building controller, is used in recognition in which the centralized building recognizes the building controller; and a collective entrance device ID that, when the centralized building is called by one of the residential room master devices via the building controller, is used in recognition in which the one residential room master device recognizes the building controller as a virtual collective entrance device that is different from the collective entrance devices.

In an intercom system to be used in an apartment complex configured by residential buildings and a centralized building that can communicate with the residential buildings, the residential buildings includes: residential room master devices disposed in residential rooms, collective entrance devices which can communicate with the residential room master devices; and a building controller. The building controller has: a building controller ID that, when the centralized building is called by one of the residential room master devices via the building controller, is used in recognition in which the centralized building recognizes the building controller; and a collective entrance device ID that, when the centralized building is called by one of the residential room master devices via the building controller, is used in recognition in which the one residential room master device recognizes the building controller as a virtual collective entrance device that is different from the collective entrance devices.

The intercommunication system according to the invention is an intercommunication system used in an apartment complex comprising plural residential buildings. Each of the plural residential buildings is equipped with room parent devices installed in respective rooms; a collective entrance device which enables a call manipulation for calling one of the room parent devices; and a building control unit which connects, by an intercom line, the collective entrance device and the room parent devices of the respective rooms of the residential building. The collective entrance device has a storage unit which is stored with terminal information of the collective entrance device. The building control units of the plural respective residential buildings are connected to each other by a network in which a communication is performed according to a general-purpose protocol and can communicate, over the network, with an external apparatus that is connected to an external network.

The intercommunication system according to the invention is an intercommunication system used in an apartment complex comprising plural residential buildings. Each of the plural residential buildings is equipped with room parent devices installed in respective rooms; a collective entrance device which enables a call manipulation for calling one of the room parent devices; and a building control unit which connects, by an intercom line, the collective entrance device and the room parent devices of the respective rooms of the residential building. The collective entrance device has a storage unit which is stored with terminal information of the collective entrance device. The building control units of the plural respective residential buildings are connected to each other by a network in which a communication is performed according to a general-purpose protocol and can communicate, over the network, with an external apparatus that is connected to an external network.

An intercom network for real-time audio communication between users has a stationary element to which the users are connected, a mobile terminal that comprises an audio input and that can transmit audio signals wirelessly to the stationary element or to another user, and a device in the stationary element for user management, that administers the users connected to the stationary element, and that carries out an authorization check for logging the mobile terminal onto the stationary element. An NFC element is provided in the device on the stationary element, and an NFC counter-element is provided on the mobile terminal that can transmit authorization information to the NFC element when the mobile terminal approaches the stationary element.

An intercom network for real-time audio communication between users has a stationary element to which the users are connected, a mobile terminal that comprises an audio input and that can transmit audio signals wirelessly to the stationary element or to another user, and a device in the stationary element for user management, that administers the users connected to the stationary element, and that carries out an authorization check for logging the mobile terminal onto the stationary element. An NFC element is provided in the device on the stationary element, and an NFC counter-element is provided on the mobile terminal that can transmit authorization information to the NFC element when the mobile terminal approaches the stationary element.

Methods and systems for granting access to a building are disclosed. The system includes a telephone entry system associated with the building, a processor in communication with the telephone entry system, a non-transitory computer readable medium. The non-transitory computer-readable medium includes one or more programming instructions that when executed by the processor, cause the processor to receive a request including an access code for access to the building code, determine whether the access code is valid, and transmit to the telephone entry system associated with the building a sequence of dual-tone multi-frequency (DTMF) tones to cause the telephone entry system to grant access to the building in response to determining that the access code is valid.

An intercom system includes a dwelling parent device installed in each dwelling, a collective foyer device configured to communicate with the dwelling parent device, and a control device configured to control the collective foyer device, which includes name plates on each of which a resident name for specifying a dwelling parent device of a resident is displayed so a visitor may call the resident, and dedicated buttons correlated with the name plates and capable of receiving an operation for calling the dwelling parent device corresponding to the resident name displayed on each name plate. The collective foyer device or the control device includes a calling table in which location numbers for specifying locations of dedicated buttons in a region of the collective foyer device are assigned. The respective resident names are assigned to the location numbers of the dedicated buttons visually recognizable to the visitor, on the calling table.