Fixed subscriber unit

Details Fixed subscriber unit Fixed subscriber unit

1998-05-18

2001-11-06

{haeck over (S)}mits, T{overscore (a)}livaldis Ivars (Department: 2641)

Telecommunications

Transmitter and receiver at separate stations

Having measuring, testing, or monitoring of system or part

C455S573000, C379S413000

Reexamination Certificate

active

06314270

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fixed subscriber unit in which at least one telephone set connected thereto by wire can send and receive calls by radio to and from and speak with another telephone set connected to a public telephone network, or more particularly to a fixed subscriber unit in which the user is supplied with the information as to whether the fixed subscriber unit is driven by an AC/DC adaptor or by a power back-up charge battery unit and so on.
2. Description of the Related Art
FIG. 1
is a block diagram showing a configuration of a conventional fixed subscriber unit. A conventional fixed subscriber unit
1
is connected by wire to one or a plurality of telephone sets for sending and receiving through an antenna
2
a radio wave to and from a base station (not shown) connected to a public telephone network. A radio section
3
demodulates the signal received from the antenna
2
into an audio signal on the one hand and modulates the audio signal from the telephone
13
and transmits it by way of the antenna
2
on the other hand. A two-wire/four-wire converter
4
converts two telephone wires for connecting the telephone set
13
to a total of four wires including two transmit wires and two receive wires to be connected to the radio section
3
. In the case of a non-balanced circuit, one of the two transmit or receive wires is connected to the earth and is not shown.
A ringing tone generator
6
sends out a ringing tone for sounding the ringer of the telephone set
13
. A relay
7
switches the telephone wires for connection to the telephone
13
between the two-wire/four-wire converter
4
and the ringing tone generator
6
. A hooking detector
8
is for detecting the on/off-hook state of the telephone set
13
by monitoring the current in the telephone wire connected to the telephone set
13
. A DTMF detector
9
detects a DTMF signal sent by the telephone set
13
. A DT·BT generator
10
generates a DT (dial tone) and BT (busy tone) to be sent to the telephone set
13
.
A controller
21
controls the radio section
3
, the ringing tone generator
6
, the relay
7
and the DT·BT generator
10
by the signals from the radio section
3
, the hooking detector
8
and the DTMF detector
9
, so that the telephone set
13
can send and receive a call and speak by radio with other telephone sets connected to the public telephone network. The telephone set
13
is connected by wire to the fixed subscriber unit
1
.
A power circuit
12
supplies a DC voltage to each part in the fixed subscriber unit
1
. An AC receptacle cable
14
transmits an AC voltage from a home AC receptacle to an AC/DC adaptor
15
. The AD/DC adaptor
15
converts an AC voltage to a predetermined DC voltage and outputs the DC voltage.
A power back-up charge battery unit
16
supplies a DC voltage, when supplied from the AC/DC adaptor
15
, directly to the power circuit
12
while at the same time charging the charge battery thereof, if the battery is not sufficiently charged. In the case where the DC voltage is not supplied from the AC/DC adaptor
15
due to a power failure or the like cause, the DC voltage of the charge battery is supplied to the power circuit
12
. This power back-up charge battery unit
16
can be either built in or attached to the exterior of the fixed subscriber unit
1
.
Now, the operation of the conventional fixed subscriber unit will be described. In
FIG. 1
, upon receipt of a call from another telephone through a radio base station, the controller
21
receives call-in information from the radio section
3
. Then, the controller
21
controls the ringing tone generator
6
and the relay
7
to send out a ringing tone to the telephone set
13
. When the telephone
13
goes off the hook, the controller
21
acquires the off-hook information from the hooking detector
8
, controls the relay
7
and connects the telephone
13
with the other telephone for transmitting and receiving signals through the antenna
2
, the radio section
3
and the two-wire/four-wire converter
4
.
In this way, the conventional fixed subscriber unit
1
makes possible speech by radio between at least one telephone set connected by wire to the fixed subscriber unit
1
and other telephone sets connected to the public telephone network.
As to the power system, the AC voltage obtained from a home AC receptacle is converted into a fixed DC voltage by the AC/DC adaptor
15
, and supplied to the power circuit
12
through the power back-up charge battery unit
16
. In the process, the power back-up charge battery unit
16
, if the charge battery thereof is not sufficiently charged, supplies the DC voltage of the AC/DC adaptor
15
to the power circuit
12
while at the same time charging the charge battery thereof. In the case where the DC voltage output of the AC/DC adaptor is stopped due to a power failure or a loosened AC receptacle, the DC voltage output of the charge battery in the power back-up charge battery unit
16
is supplied to the power circuit
12
, so that the operation of the fixed subscriber unit
1
is made possible for a time period during which the DC output voltage of the charge battery is maintained in a certain range.
In the above-mentioned fixed subscriber unit
1
described above, the user cannot not be informed in the case where the DC voltage output of the AC/DC adaptor
15
stops due to a power failure or a loosened AC receptacle cable
14
and the fixed subscriber unit
1
is driven by the output voltage of the charge battery of the power back-up charge battery unit
16
. The user is, therefore, neither informed that the remaining available speech time is limited since the power for the operation is supplied from the power back-up charge battery unit
16
.
SUMMARY OF THE INVENTION
The object of the present invention is to solve the above-mentioned problems of the prior art and to provide a superior fixed subscriber unit comprising means for judging whether the fixed subscriber unit is driven by the voltage output of an AC/DC adaptor or by the charge battery in a power back-up charge battery unit, and means for visually or aurally transmitting the related information to the user.
According to the present invention, there is provided a fixed subscriber unit connected to at least one telephone set by wire, comprising a radio section for transmitting and receiving signals to and from a base station connected to a public telephone network, a signal processing section for processing signals between the telephone set and the radio section such that the telephone set can communicate with another telephone set connected to the public telephone network, a power circuit for supplying electric power to each section of the fixed subscriber unit when connected to a power back-up charge battery unit connectable to an AC/DC adaptor for outputting a DC voltage when supplied with electric power from an external AC power supply, voltage measuring means for measuring an output voltage of the power back-up charge battery unit, comparator/judging means for comparing the measured voltage with a predetermined voltage and judging whether the power circuit is supplied with electric power from the external AC power supply through the power back-up charge battery unit or only from the power backup charge battery unit, and notification means for notifying an user of information relating to the power back-up charge battery unit on the basis of judgment of the comparator/judging means. The notification means can visually or aurally notify the user whether the power circuit is supplied with electric power from the external AC power supply or only from the power back-up charge battery unit. As a result, the user can select an appropriate method of using the fixed subscriber unit according to the prevailing conditions.


REFERENCES:
patent: 5333176 (1994-07-01), Burke et al.
patent: 5343136 (1994-08-01), Yamaguchi et al.
patent: 5603095 (1997-02-01), Uola
patent: 5726636 (1998-03-01), Hayes, Jr.
patent: 5838771 (1998-11-01), Moeller
patent: 5901361

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