Note: Descriptions are shown in the official language in which they were submitted.
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Field Of The Invention
This invention relates to telephone systems, and
in particular a structure and method for allowing a single
telephone line to participate in dif~erent hunt groups.
Backqround To The Invention
When a person i5 away from his telephone but
wishes incoming calls to be answered, usually one of two
te~hn;ques is used to provide this result: call forwarding,
and hunt group implementation.
In call forwarding, a destination line number i~ ;
registered against a single telephone lin~, which is used by
the telephone switching system to which to route incoming
calls.
Using hunt groups, a group of telephone lines are
listed against a single telephone line, and when
implemented, each of the listed telephone lines in the group
is rung for incoming calls to that single telephone line.
Plural lines can designate the same hunt group, so that, for
example, in night service all telephone calls to any of many
telephones will ring all telephone lines of the group, so
that a person such as maintenance staff working late within
hearing range of one of the telephone lines of the group
could take the call. When hunt groups are designated in a
central office, a telephone line can only be a member of a
single hunt group, for at least billing consi~erations.
Some telephone lines have plural telephone
numbers. For example, a telephone line can be rung with one
ringing cadence when an incoming call is to one number
associated with that line, and with a different cadence when
an incoming call is to a different number associated with
that line. It has not been possible to include such lines
in hunt groups.
Summary Of The Invention
The present invention provides for each of plural
station numbers associated with one talephone line to be
members of plural hunt groups. Thus, for example, if one
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station number (e.g. teleph4ne directory number) is the
master number of a home, and a secondary station number is
associated with a teen-ager living in the same home, when
the teen-ager wishes to receive calls at any of plural homes
of friends the teen-ager can invoks a hunt group which is
headed by the secondary number. All incoming calls to the
secondary number will ring the telephone lines in that hunt
group.
In accordance with one embodiment, all of the
lines of the hunt group will ring using a distinctive
ringing cadence for the secondary number~ With the teen-
ager being at the home of a friend who has a telephone
nu h~r that is in the hunt group, he and persons at each o~
the telephones which have numbers in the hunt group can
distinguish incoming calls to the teen-ager because of the
distinctive cadence, from calls to the master numbers of the
various telephones, and the master number of the telephone ;~
at the home of the teenager.
In accordance with another embodiment, if the
secondary number is listed in a hunt group which is headed
by a designator of a different telephone, for example when a
hunt group is set up by the friend of the teenager, which
contains the (secondary) telephone num~er of the teenager,
with incoming telephone calls to the friend, the telephone
lines listed in the hunt group will be rung, but the -
telephone line of the teenager will be rung usiny the
distinctive cadence of the number of the teenager, allowing
the parents of the teenager to ignore the ringing.
In accordance with another embodiment of the
invention, a telephone switching system is comprised of at
least one telephone line having multiple station numbers,
apparatus for storing a first hunt group list of numbers
designating plural stations including a pilot number and a
ni h~r designating one of the multiple station numbers, and
apparatus for receiving the pilot number and in response
ringing each of the plural designated stations including the
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one o~ the multiple station numbers, whereby a station
connected to the one telephone line can be rung.
In accordance with another embodiment, a telephone
switching system is comprised of apparatus ~or storing hunt ~-
group lists relating to groups of telephone lines, a single
telephone line being cont~;ne~ in more than one hunt group
list, and apparatus for ringing each of the telephone lines
relating to the separate hunt group lists.
In accordance with another embodiment, a method of
ringing a telephone line is comprised of storing different
numbers each designating the same telephone line in
different hunt group lists, receiving a call to one of the
dif~erent numbers, ringing each of the telephone lines in
the hunt group contained the one number, and ringing the
telephone line designated by the one number with a
particular ringing cadence.
Brie~ Introduction To The Drawinqs
A better underst~n~;ng o~ the invention will be
obkained by referring to the detailed description below,
with reference to the following drawings, in which:
Figure 1 is a block diagram of a system which
contains an embodiment of the invention, and
Figure 2 is a detail of the memory o~ the system
of Figure 1.
Detailed Descri~tion Of The Invention
Figure l is a block diagram illustrating a
telephone switching system, of the type described in U.S.
patents 4,615,028 issued September 30th, 1986, invented by
Conrad Lewis and Gino Totti and 4,616,360 issued October 7,
1986, invented by Conrad Lewis. It should be understood
that other telephone switching systems could be used in
place thereof.
In the system of Figure l, station sets 1 such as
telephone sets are interconnected with each other and with
trunks 2 via at least one circuit switch 3, telephone lines
4 connected to the station set being switched to circuit
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switch links via peripheral controls 5 which interface the
telephone lines and trunks via peripheral interface circuits
(PICs) 6. Ringing generators 7 are connected to the
peripheral controls 5 in order to provide ringing signals to
S the telephone lines. Random access memories (RAMs) 8 are
also connected to the peripheral controls 5, which store -
control signals for operation of the peripheral controls. ~;
A processor (main control) 10 is connected via a
main bus 12 to the circuit switch 3, to control it's
operation. A message switch 13 is also connected to bus 12
and to peripheral controls 5, to receive control messages
from processor 10 and to route them to peripheral control 5,
for storage in memories 8 or for transmission to telephone
lines 4, destined for the station sets 1. A system memory
14, connected to bus 12, contains control programs and data
used by the processor for controlliny the operation of the
system. An operator console 16 is connected to the main bus
12, which is used to configure and test the system when
required.
In accordance with the present invention, a hunt
group memory 17 is connected to bus 12, for read and write
access by processor 10. This memory is used to store hunt
group tahles.
With reference to Figure 2, the details of an the ~;
present invention will be described.
Using the operator console 17, for example, an
operator who has been asked to prepare a hunt group prepares
a hunt group such as hunt group list 18 with members
designated by the subscriber (e.g. the teen-ager). The hunt
group is headed by a pilot number, which can be either a
special number stored in a table and associated with the
subscriber number, or can be the subscriber number itself.
The hunt group list should also contain the subscriber
numbers of the other m~mbers of the hunt group, as shown.
This list is converted, if necessary, to a hunt group table
20, which is headed by the pilot number of the subscriber,
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and lists information designating each of the stations
(tel~phone lines and numbers associated therewith) of the
other h~rs of the hunt group.
Contained within system memory 14 are station
S tables 22. Each station table retains information used by
the switching system about the characteristics of each
station number, for example the classes of service allocated
to each station number. One of the characteristics stored
in station tables 22 is the ringing cadence of each station
number.
Each of the station identifiers stored in the hunt
group tales 20 contains a pointer to a particular station
table 22.
The system memory 14 contains a table 24 which is
looked up as a result of an incoming call, referred to
herein as a digit tree table. This table contains reference
to the station associated with each incoming telephone
number, and in particular a pointer to the station table 22
containing the station characteristics so that the processor
can avail itsel~ of the information stored in the station
table for a particular incoming call and properly process
the call. For example, incoming dialed digits 5110103 has
an entry in digit tree table 24, and a cross-reference to
station y. This cross-reference is a pointer to the station
table carrying the characteristics of station y.
In the present invention, when a hunt group is set
up the digit tree replaces the cxoss-reference to a
particular station table of a particular subscriber for
which the hunt group is set up, with reference to a
corresponding hunt group table ~0. Each of the members of
the hunt group also has its own pointer to a particular
station table 22.
In the case that a particular telephone line has ~ ;
two different station numbersl each appears on a separate
station table. Each of those station tables can contain
data causing different ringing cadences to be used.
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Thus for an incoming call to a number which is the
pilot number, or which designates the pilot number of one
hunt group table, a station designated in that hunt group
will be only one of the numbers of the multi-number station. ;
S That one number will point from the hunt group to a
particular station table. The data relating to that station
number is retrieved by the processor, and is transmitted to
the peripheral control ~or controlling the ringing of that
station in the hunt group in accordance with the particular
ringing cadence stored in the pointed~to station table.
The other station number can be contained in a ~
different hunt group. When an incoming call is placed to a ~'
station designating the pilot number (which can be that
other station number), the hunt group table points to the
station table relating to that other station nl her. The
ringiny cadence is retrieved, which ringing cadence will
typically be different from that of the cadence associated
with the first station number.
In this case, all station numbers in a hunt group
are rung with the particular cadence stored in association
with it in its station table. With the pilot station number
designating as part of the hunt group it's own station
nl h~r, its own station number will be rung using its own
particular ringing cadence.
However, instead of using the cadences stored in
each of the station tables associated with each station
listed in the hunt group tables, thP processor can look up
the station table of the pilot station, retrieve the ringing
cadence, ignore the ringing cadences of the station table~
for each o~ the stations in the hunt group table, and cause
each of the stations in the hunt group to ring with the
distinctive cadence of the hunt group pilot. Thus the
subscriber located at any of the stations will recognize his
own ringing cadence, and know that the call is ~or him,
while others at those stations will not recognize the
cadence and knaw that the call i5 not for them.
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A person understanding this invention may now
design variations and improvements, using the principl~s
described herein, and falling within the scope of the claims
appended hereto. All such structures are considered to be
S part of the present invention.
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