referring to fig1 , an example of an ip telephone automatic response apparatus according to the invention will be described . the ip telephone automatic response apparatus in this example comprises a voip terminal 10 and a database 20 . voip terminal 10 includes an ip telephone portion 11 , a display portion 12 for displaying a response method which is set by the user or information from the database , and an input portion 13 for setting response methods and controlling the originating call and / or destination call on voip terminal 10 . ip telephone portion 11 includes a voip portion 111 with ip telephone functions and an automatic response switching portion 112 for automatically switching the response method upon reception of a call . database 20 includes a first and a second response method table 21 and 22 , a first and a second schedule table 23 and 24 , response message form data 25 , and message data ( answerphone message ) 26 . the data registered in response message form data 25 and the data stored in message data ( answerphone message ) 26 may be of any data format , such as voice , text , or image , for example . while there are shown in fig1 one voip terminal 10 and one database 20 , the ip telephone automatic response apparatus may be arranged to include a plurality of voip terminals 10 and one database 20 . database 20 may be of any form as long as it can be referred to by all voip terminals 10 , and it may be installed anywhere , such as on the network , for example . voip terminal 10 may be either a fixed terminal , such as a subscriber telephone or a computer , or a mobile or portable terminal such as a cellular phone or a pda . in the following description , however , voip terminal 10 will be assumed to be a portable terminal . in first response method table 21 , relationship between a position information table and response methods is registered , as shown in fig3 . in second response method table 22 , relationship between urgency and response methods is registered , as shown in fig7 . in first schedule table 23 , relationship between time information tables and plans is registered , as shown in fig4 . in second schedule table 24 , relationship between a time information table and plans and , further , group ids and the names of registered personnel , for example , are registered , as shown in fig5 . in response message form data 25 , message forms to be transmitted to the originating caller are registered . in message data ( answerphone message ) 26 , messages transmitted from the originating caller are stored . the first and second response method tables 21 and 22 , first and second schedule tables 23 and 24 , and response message form data 25 are entered by the user in advance . details of the response method utilizing these tables will be described below . referring to fig2 , an example of an ip telephone system utilizing the ip telephone automatic response apparatus of the invention will be described . a living room , a conference room , and a dinning room are each furnished with a network , namely a living room network 410 , a conference room network 420 , and a dining room network 430 , respectively . the networks include routers 41 , 42 , and 43 , respectively , through which the networks are connected to the internet 200 . an ip address is allocated to each voip terminal . the ip address consists of a network address and a host address . the network address is the portion of the ip address that identifies the network , and the host addresses of which are all zero . different network addresses are given to living room network 410 , conference room network 420 , and dining room network 430 , respectively , so that they are identified as different network segments . thus , the network address indicates the position where the router is installed . the network address further indicates the current position of the voip terminal . the network address uniquely corresponds to the current position of the router and the voip terminal . a case will be considered that a voip terminal 411 existing in living room network 410 is called by a voip terminal 401 on the call originating side . the originating call from voip terminal 401 is sent out via router 40 to the internet 200 , from which it is further transferred , via router 41 , to voip terminal 411 on the call destination side . voip terminal 411 detects the network address based on the ip address of its own voip terminal 411 or voip terminal 401 on the call originating side . voip terminal 411 further refers to a database 20 to obtain a response method corresponding to the network address . then , an automatic response switching portion 112 carries out a call reception process or call destination process in accordance with the response method . thus , in this example , voip terminal 411 on the call destination side carries out a response process in accordance with the current position of voip terminal 411 on the call destination side or that of voip terminal 401 on the call originating side . fig3 shows an example of first response method table 21 , which includes a position information table and corresponding response methods on the call destination side . the position information table includes a corresponding relationship between network addresses and installed positions . as described with reference to fig2 , the relationship between the network address and the installation position of the router is uniquely determined . automatic response switching portion 112 of the voip terminal on the call destination side extracts a response method based on the network address of the call destination side or call originating side , referring to response method table 21 . the response methods on the call destination side include “ answer the call ,” “ response message form ,” and “ refer to schedule table .” the user selects from a prepared list of response methods one for each particular position , and then registers it . when “ answer the call ” is set as the response method , a normal ip telephone call reception process is performed . this is the case where the call destination side is able to answer the call , for example . when “ response message form ” is set as the response method , response message form data 25 stored in the database is transmitted to voip terminal 401 on the call originating side . this is the case where the call destination side is unable to answer the call , for example . if a message is transmitted from voip terminal 401 on the call originating side in response to the response message form , the content of the message is stored in message data ( answerphone message ) 26 in the database . when “ refer to first schedule table ” is set as the response method , automatic response switching portion 112 refers to first schedule table 23 in the database . when “ refer to second schedule table ” is set as the response method , automatic response switching portion 112 refers to second schedule table 24 in the database . now referring to fig4 , an example of first schedule table 23 will be described . in this example , schedule table 23 includes a time information table and corresponding “ plans ” of the destination caller . the time information consists of “ date information ” and “ time information .” the “ plans ” store schedule descriptions , such as a conference , a meeting , and so on . the “ plans ” may be selected from a prepared list of plans or may be prepared based on character strings entered by the user . automatic response switching portion 112 obtains a plan registered in the row of the date information and time information that correspond to the time of reception of the call . the obtained plan is then transmitted to voip terminal on the call originating side as response message data . this response message may be of any data format , such as voice , text , or image , as mentioned above . if there is no plan registered in the row of the date information and time information corresponding to the current time , automatic response switching portion 112 obtains a response method by referring to first response method table 21 . referring now to fig5 , an example of second schedule table 24 will be described . schedule table 24 of the present example differs from first schedule table 23 of fig4 in that the schedules of other members as transfer destinations are also registered . schedule table 24 includes group ids , names of registered people , ip telephone numbers , transfer priority , and current positions , in addition to the time information table and the plan of the call destination side . the designation “ current position ” indicates a new location of the voip terminal as it moves into a different network . the manner in which “ current position ” is set will be described later . automatic response switching portion 112 determines whether or not any plan for the individual destination caller is registered in the row for the date information and time information corresponding to the time of reception of a call . if no plan is registered for the individual destination caller , automatic response switching portion 112 obtains a response method by referring to first response method table 21 . if a plan is registered for the individual destination caller , first the names of registered personnel with the same group id as the destination caller are retrieved . then , one of those registered personnel that have no registered plan in the row of the date information and time information corresponding to the time of reception of the call is selected as the transfer destination . the name of the registered person selected as the transfer destination , the ip telephone number , transfer priority , current position , and response message form data are transmitted to voip terminal 401 on the call originating side . fig6 shows a transfer selection window displayed on display portion 12 of voip terminal 401 on the call originating side . in the transfer selection window , there are displayed a transfer destination list 62 of transfer destinations , check boxes 61 for selecting a transfer destination , response message contents 63 , a transmission button 64 , a cancel button 65 , and a answerphone button 66 . in transfer destination list 62 , transfer destinations transmitted from the voip terminal on the call destination side are displayed from top to bottom in the order of decreasing priority . in response message contents 63 , a response message transmitted from the destination caller is displayed . as the originating caller selects the name of a registered person and presses transmission button 64 , the originating call is transferred to the selected destination . the originating caller may either transmit a message by pressing answerphone button 66 , or terminate the connection by pressing cancel button 65 . referring to fig7 , an example of second response method table 22 will be described . second response method table 22 is made up of urgency and corresponding response methods . urgency is expressed by flags a , b , c , and d with decreasing order of urgency , for example . the destination caller registers response methods corresponding to the importance and / or urgency , via input portion 13 . in the present example , urgency a indicates that a call should be answered , urgency b indicates that a call should be transferred , urgency c indicates that first response method table 21 should be referred to , and urgency d indicates that a response message form should be transmitted . alternatively , the flags may be set such that a call should be answered for urgency b and higher urgency and a response message form should be transmitted for urgency c and lower urgency . upon making an originating call , the originating caller sets the urgency using input portion 13 , such that an urgency flag is transmitted to the destination caller together with other data . automatic response switching portion 112 on the call destination side obtains the urgency flag from the received data and extracts the response method by referring to the second response method table . a process is then performed in accordance with the extracted response method . for example , if the urgency is a , a call - answering process is performed , and if the urgency is b , a transfer process is carried out by referring to the second schedule table . hereafter , a method for registering the position information in the database 20 as current position information after the voip terminal has moved into a different network segment will be described . a new ip address is allocated to the voip terminal when the terminal moves into a different network segment . the current position of the voip terminal is obtained from the network address of the new ip address . the voip terminal then transmits the current position information to the database 20 again , whereby the current position data in second schedule table 24 is updated . in accordance with ipv4 ( internet protocol version4 ), when the ip address is set manually , generally the user does not know in what network segment the current position is in or if the current position has moved into a different network segment . thus , the user transmits the current position information to the database 20 at predetermined time intervals . when the setting is such that the ip address is automatically obtained , a new ip address is distributed upon change of the network segment . thus , the user can know when the current position has moved into a different network segment . therefore , the current position information is transmitted to database 20 upon detection of movement . in ipv6 ( internet protocol version6 ), ip addresses can be automatically obtained , so that the current position information is transmitted to database 20 by the latter method . as a result , the current position of the user is registered as the current position in second schedule table 24 . while specific examples of the present invention have been described above , it will be understood that the invention is not limited thereto , and that changes and variations may be made without departing from the spirit or scope of the following claims . in accordance with the invention , when a call is received , a response can be made in a desired manner depending on the position or condition of the call destination side . in accordance with the invention , when a call is received , the method of response by the voip terminal on the call destination side can be automatically switched depending on the position of the voip terminal on the call destination side or call originating side .