本发明涉及用于建筑物外部的通信网络（104）和建筑物的内部通信网络（102）的建筑物的内部通信实体（111,112，121,122）的建筑物外部通信服务器（108）之间的控制通信，包括接入点（110，120）： 存储器（202，212），用于存储认证数据用于发起到建筑物外部通信网络（104）的通信服务器（108）的通信连接; 为了监测用于建立到建筑物外部通信服务器（108）的通信的第一通信接口（106，116）使用所存储的认证数据，其中，所述第一通信接口（106）是所述通信链路的所述建筑物外部通信服务器（108）和失败 通信链路，以产生一个故障信号; 和用于与通信的第二通信接口（107，117），所述存储在接收到故障信号，以响应该建筑的内部通信网络（102），其中，所述第二通信接口（107，117）被设计，的通信实体（111,112，121,122） 认证数据来发起该建筑的内部通信实体（111,112，121，122）和所述建筑物外部通信服务器（108）之间的通信链路（316）连接到室内通信实体（111,112，121,122）发出。

The invention relates to an access point (110, 120) for controlling a communication between a building external communication server (108) of a building external communication network (104) and a building's internal communication entity (111, 112, 121, 122) of a building's internal communication network (102), comprising: memory (202, 212) for storing authentication data for initiating a communication connection to the communication server (108) of the building external communication network (104); To monitor a first communication interface (106, 116) for establishing a communication to the building external communication server (108) using the stored authentication data, wherein the first communication interface (106) is configured, the communication link to the building external communication server (108) and failure of the communication link to generate an error message; and a second communication interface (107, 117) for communicating with said communication entity (111, 112, 121, 122) of the building's internal communication network (102), wherein the second communication interface (107, 117) is configured, in response to receipt of the alarm message, the stored authentication data for initiating a communication link (316) between the building's internal communication entity (111, 112, 121, 122) and the building external communication server (108) to the in-building communication entity (111, 112, 121, 122) send out.