Element terminal and communication system

An element terminal connected to a communication network, comprising;

• a computer including a central processing unit that executes programs loaded onto memory to implement functions of:
• a timer value storage for storing a timer value used for counting a cycle for transmitting a connection request to a management control device for managing the element terminal, via the communication network;
• a counter for reading the timer value in the timer value storage and counting the cycle indicated by the timer value;
• a connection request transmission part for transmitting the connection request to the management control device via the communication network, every time when the counter finishes counting the cycle indicated by the timer value;
• an event detector for detecting an event having occurred in the element terminal;
• and
• a timer value modifier for modifying the timer value in the timer value storage, to a value indicating a shorter cycle within a range limited to a minimum value which is predetermined, upon detecting the event by the event detector, wherein:
• the connection request transmission part further transmits the connection request to the management control device via the communication network, upon detecting the event by the event detector, and
• the timer value modifier modifies the timer value in the timer value storage to a value indicating a longer cycle within a range limited to a maximum value being predetermined, upon receiving a message indicating there is no processing request from the management control device, via the communication network.