Call management services to telephone devices which are connected to afixed wireless access subscriber unit

A method of providing call management services to a conventional wireline telephony device (or devices) which receive telephony services by means of a fixed wireless access subscriber unit. Such a subscriber unit (SU) includes a wireless transceiver for communicating with a wireless network and a telephone subscriber line interface which connects to a telephone subscriber line to which the telephony devices are connected. Such a subscriber unit is configured to carry out the following steps. Upon receipt of an incoming message (which typically occurs during call set up of an incoming call) subscriber unit evaluates whether call management services information is present, and if so searches the message, according to the wireless protocol for the CMS information and extracts the CMS information. The SU then interprets the received information, determines what information should be passed to the telephony devices to the SU and produces a message containing the relevant information which is then sent to the telephony devices via the telephone subscriber line. The new message may contain information not present in the original incoming message. This new information is retrieved from a user selected directory stored within the SU. The SU may contain a plurality of transceivers and a plurality of subscriber line interfaces wherein said subscriber unit can effectively act as a wireless key system.

FIELD OF THE INVENTION 
This invention relates to the communication systems which provide analog 
telephony services via a two-wire analog subscriber line (hereafter 
referred to as telephone subscriber line) wherein said telephone 
subscriber line is not connected to a central office switch using the 
conventional two-wire analog telephone subscriber line interface. In 
particular, the invention is particularly suited for fixed wireless access 
(FWA) applications which provide telephony services to conventional 
telephone devices via a wireless communications link. 
This application is related to Pepper, Simulating Changes in Telephone 
Subscriber Line, filed concurrently herewith, the specification which is 
hereby incorporated by reference. 
BACKGROUND OF THE INVENTION 
The use of wireless communication systems to provide telephony service has 
been seen to provide several advantages over conventional wireline 
networks. These advantages include speed of deployment, lower cost of 
installation, and reduced maintenance of outside plant. 
Conventional cellular-like terminals can be used for providing fixed 
wireless access (FWA) as well as conventional mobile cellular telephony. 
However, in order to reduce costs it is advantageous to use terminals 
designed for fixed wireless access only. Cost savings can be achieved as 
such terminals do not require mobility (in the conventional cellular 
sense) and also can be larger as a result. 
To reduce costs further, a fixed wireless access terminal can use existing 
cellular networks for providing telephony service and hence there is no 
need to deploy a separate FWA cellular system. Additionally, a FWA 
terminal can reuse the technology and components originally designed for 
conventional cellular service. 
Systems have been described for interfacing a standard conventional 
wireline telephone to a radio transceiver to enable such a standard 
telephone (or other device) to use the cellular network for providing 
telephony service. Such an interface device for connecting a cellular 
radio transceiver to a conventional telephony device is not new. For 
example, U.S. Pat. No. 4,658,096, naming West et al as inventors, 
describes an interface arrangement for connecting a conventional telephone 
set to a cellular transceiver such that the cellular network can provide 
telephony service to such a telephone set. This patent describes an 
interface which includes means for automatically determining when the user 
of such a telephone set has finished dialling, as the concept for 
connecting a telephone to cellular transceiver was known in the 
"radio-patch" art. The above cited West patent is known in the art, and 
has been cited many times in subsequent patents dealing with further 
aspects of connecting a cellular transceiver to a telephony device. Such 
systems, which may be adequate for providing POTS (plain ordinary 
telephone service) service, do not adequately support more advanced 
features, for example, call management services provided by conventional 
land line networks. 
Call management services (hereafter CMS) include, for example, Calling 
Number Delivery (CND), Message Waiting Indicator, Time of day delivery, 
Calling Line Identification (CLID), Dialable Directory Number (DN), Reason 
for Absence of DN, Reason for Redirection, Call Qualifier, Name of Calling 
Party and Calling Identity on Call Waiting (CIDCW) by means of messages 
sent to a telephone unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The present invention will be described with respect to a preferred 
embodiment used in a fixed wireless access system. It should be 
appreciated by a person skilled in the art that the invention can also be 
utilized in other types of systems, for example, fiberoptic, cable TV, 
etc. which provide telephony services by some means other than a telephone 
subscriber line connected to a central office switch using the 
conventional two-wire analog telephone subscriber line interface. 
By way of example, FIG. 1 illustrates a communications network 1000 which 
in this example includes a wireless base station which communicates by a 
medium 1100, which in this example is a suitable radio frequency interface 
(e.g., IS54B), with a subscriber unit (SU) 1200. Subscriber unit 1200 
includes a communication interface which communicates with the 
communication network 1000 via the medium 1100. In this example, 
communication interface comprises a radio transceiver and antenna 1215 for 
communicating using IS54B protocols with base station 345. Subscriber unit 
1200 also includes terminal unit which includes a primary handset 1240 and 
a SLIC 1230 which connects to telephone subscriber line 1250 which 
connects to telephone 380. Additional telephony devices (not shown) can be 
connected to the line 1250. Telephone subscriber line 1250 can include 
wiring within a building, extension wires, or a combination thereof. 
FIG. 1 also illustrates an example of the SU 1200 receiving a call from a 
telephone connected to the PSTN. In this example a telephone 310 connects 
with a PSTN Central Office 340 which in turn is coupled to an MSC 342 
which is coupled to a base transmitter station BTS (in this example via a 
BSC 345) which transmits via antenna 350. Subscriber unit 1200 is coupled 
to a conventional telephone set 380 which supports call management 
services features. 
In operation central office 340 sends call management services information 
to the MSC 342 about telephone 310 when telephone 310 attempts to place a 
call to subscriber unit 1200. This information 320 is formatted according 
to the specific trunk protocol used to connect the PSTN 340 to the MSC 
342. This information is translated from the trunk protocol to the IS54B 
protocol by the MSC 342. The information in IS54B form is then 
transmitted, as shown at 360 in the form of an "alert with info" message 
sent over the radio link from the base station to the subscriber unit 
after completion of the paging process. The SU 1200 receives the IS54B 
coded message over the air interface and then decodes said message to 
extract the desired call management services information (e.g. calling 
party number). This decoding process is performed by the baseband 
microcontroller 90 and sent to the VF microcontroller 180 in an 
intermediate format (as described below). The VF microcontroller then 
carries out several central office functions as will be described below in 
order to send a