Call processing method, subscriber unit, and access control apparatus operated in wireless local loop system

A subscriber unit in a wireless local loop system having an access control apparatus connected to a local exchange of a public switched telephone network via an inter-network interface, having the subscriber unit connected to the access control apparatus via a radio connection and having a user terminal connected directly to the subscriber unit, comprising:

• a dial tone reception guarantee device to guarantee reception of a dial tone by the user terminal, after activation thereof, irrespective of the conditions in said local exchange, the dial tone being generated by and output from the subscriber unit, instead of said local exchange, to said user terminal, upon receipt of a send command which is issued by the access control apparatus, the send command being transmitted to said subscriber unit, the dial tone being stopped upon receipt of a stop command which is issued by the access control apparatus, the stop command being transmitted to the subscriber unit when the access control apparatus detects the first dialed digit.

An access control apparatus in a wireless local loop system having the access control apparatus connected to a local exchange of a public switched telephone network via an inter-network interface, having a subscriber unit connected to the access control apparatus via a radio connection and having a user terminal connected to the subscriber unit, comprising:

• a dial tone send/stop control unit which issues and transmits a send command to a dial tone generating unit in said subscriber unit, commanding the subscriber unit to generate a dial tone, instead of said local exchange, and output the dial tone to the user terminal, the send command being transmitted to said dial tone generating unit when a signal is received from the user terminal indicating activation, and which issues and transmits a stop command for stopping the dial tone to said dial tone generating unit when a first dial digit originated from the user terminal is detected.

An access control apparatus in a wireless local loop system having the access control apparatus connected to a local exchange of a public switched telephone network via an inter-network interface, having a subscriber unit connected to the access control apparatus via a radio connection and having a user terminal connected to the subscriber unit, comprising:

• a path connection forming unit for forming a path connection to the user terminal in the period from when a first dial digit originated after the activation is received from the user terminal and a dial tone from said local exchange is stopped to when a last dial digit is received from the user terminal and a ringback tone is returned from the local exchange, said path connection being established not before said dial tone from said local exchange is stopped.

An access control apparatus in a wireless local loop system having the access control apparatus connected to a local exchange of a public switched telephone network via an inter-network interface, having a subscriber unit connected to the access control apparatus via a radio connection and having a user terminal connected to the subscriber unit, comprising:

• a VIP call processing unit activated when a disconnection message is returned from said local exchange with respect to a request for connection sent in response to activation of said user terminal, to analyze a dial number train originated from said user terminal and determine whether or not the dial number train relates to a VIP call, and if it does relate to a VIP call, sending a request for connection to said local exchange indicating that the dial number train relates to a VIP call, and if the dial number train does not relate to a VIP call, transferring said disconnection message to said subscriber unit.

An access control apparatus in a wireless local loop system having the access control apparatus connected to a local exchange of a public switched telephone network via an inter-network interface, having a subscriber unit connected to the access control apparatus via a radio connection and having a user terminal connected to the subscriber unit, comprising:

• a VIP call processing unit to analyze a dial number train subsequent to activation by said user terminal, determine whether the dial number train relates to a general call or a VIP call, and send a request for connection to the local exchange containing an indication of the result of the determination.

An access control apparatus in a wireless local loop system having the access control apparatus connected to a local exchange of a public switched telephone network via an inter-network interface, having a subscriber unit connected to the access control apparatus via a radio connection and having a user terminal connected to the subscriber unit, comprising:

• a pre-connected channel control unit to send a request for connection identifying a pre-connected channel to said local exchange when a time slot for the preconnected channel has been rejected, due to overflow at a time of channel congestion between the local exchange and the access control apparatus.

An access control apparatus in a wireless local loop system having a subscriber unit and an access control apparatus arranged between the subscriber unit and a local exchange of a public switched telephone network, the access control apparatus being connected to the subscriber unit via a radio connection and connected to said local exchange via an inter-network interface, comprising:

• a dial tone send/stop control unit to issue and transmit a send command to the subscriber unit when the access control apparatus detects that the subscriber unit has been activated, the send command commanding the subscriber unit to generate and output a dial tone, instead of said local exchange, to a user, the dial tone send/stop control unit issuing and transmitting a stop command to the subscriber unit when the access control apparatus detects that the user has input the first dialed digit, the stop command commanding the subscriber unit to stop output of the dial tone to the user.

An access control apparatus in a wireless local loop system having the access control apparatus connected to a local exchange of a public switched telephone network via an inter-network interface, having a subscriber unit connected to the access control apparatus via a radio connection and having a user terminal connected to the subscriber unit, the user terminal outputting a first dial digit after which a dial tone from the local exchange is stopped, the user terminal outputting a last dial digit after which a ringback tone is returned from the local exchange, comprising:

• a path connection forming unit for forming a path connection to the user terminal in the period from when the dial tone from the local exchange is stopped to when ringback tone is returned from the local exchange.