Note: Descriptions are shown in the official language in which they were submitted.
J. Barsellotti - 4
10f~7f~33
BACKGROUND OF THE INVENTION
In key systems as generally known, line appear-
ances at stations are hard wixed and can only be changed by
disconnection of the wires, as necessary. In addition,
special features are also connected permanently as necessary
and changed only by laborious disconnection and replacement
as has been common in the telephone industry since the
inception of cross connect distribution wiring.
In the case of key systems of the type shown in
U~S. Patent 3,935,396 issued 1/27/76, many lines can be
provided with access to stations by tLme division signaling
methods there~y minimizing the number of conductors
extending from stations to lines. In such systems, the
connection of speech conductors from lines to stations
through crosspoin~ matrices are under memory cont~ol. Larger
combtnations of station and line access are feasible with
systems of this type. However, the requirement of inflexible -
permanent wiring connections inhibit the possibility of
changing line to station allocations and for changing special
features being provided to one or more stations.
SUMMARY OF THE INVENTION
The present invention provides an apparatus for
providing a fully flexible station-line access for a key
system employing a large plurality of lines having access
to a key station. The apparatus allows the line to station
association to be changed, if necessary, by the unplugging
of panel jacks and by replugging the jacks in a different
conftgura~ion~ The jack and plug connections once made will
determine the line~ accessib}e at respective stations through
the otherwise normal use of the key system. These conne~tions
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or associations can readily be set on location by the installers, as required by
conditions in what would be a permanent connec~ion but which could readily be
changed, if necessary.
In a like manner, various special features such as restricted service (on a
per-line basis) can be changed when necessary as well as features such as ringing of a
particular line at a particular station in the event of a power failure. For a limited
number of stations, added features such as automatic hold, security operation, and
prime line pick-up can be provided to any station by proper cross-connection of cords
on the jack panel of the apparatus.
Further, stations having access to a number of lines may be readily joined
to provide additional lines with access to one of the stations up to a multiple of that
number of lines.
It is therefore an object of the invention to provide an improved apparatus
for associating stations with lines for use in key telephone systems.
It is a further object of the invention to provide a key telephone system in
which a plug-panel is provided for associating stations with lines in any pattern
desired.
It is a further object of the invention to provide as an integral part of each
key telephone system, a plug-in programming panel for associating stations with lines
or with desired special features in a fully flexible, reaidly changeable arrangement.
It is a still ~urther object of the invention to provide in a tlme division key
telephone system, an arrangment located at the key system for associating lines with
stations in a fully flexlble manner.
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. Barsellotti- 4
~RIEF DESCRIPTION OF THE [)RAWINGS:
Figure I is a schematic block diagram of -the circuit of a key telephone
system employing my invention;
Figure 2 is a layou~ drawing of the programming panel in the circuit of
Figure 1, with exemplary interconnections shown; and
Figure 3 is a perspective view of the equipment cabinet housing the system
of Figure I showing the programming panel of the invention.
DETAILED DESCRIPTION OF THE DRAWINGS:
In Figure 1, I show a block diagram for a circuit as shown by U.S. Patent
3,935,396 issued 1/27/76 for a key telephone system in which there is a Key Telephone
Unit (KTU) equipment cabinet serving a plurality of key telephone stations sets 12,14
with but one voice pair of conductors 20 and one data pair of conductors 22 between
the equipment cabinet and each station set such as station set 12.
Within the station set 12, there is a Da~a Modem and Logic Unit 30 and a
plurality of line select buttons 32 and associated line lamps 34, one lamp and button
per line, as is well-known. Shown is a ten-line station set with ten line buttons 32, a
hold button 35, a miscellaneous services button 36 (which could be a conference
button, for example) and a secrecy button 38. A telephone handset 40 is shown
provided with a hookswitch 42, the hookswitch providing input to the data modem.
~ s mentioned, four wires ~two data and two
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J. Barsellotti - 4
1067633
speech wires) connect the station set to the control
equipment. The two wires forming the voice pair connect
the telephone instrument or handset to conductors of one
multiple of a relay contact matrix section 50 of a correspond-
ing station circuit 54 of the KTU equipment cabinet. Each
station is associated with a station circuit through the
voice pair on the matrix and th~ data pair in the station
control~ Each matrix comprises a tree of relay contacts
controlled by a plural relay drive 51, the relays being
controlled from the station logic and memory 53. The two
wires for the data pair connect the modem 30 in the station
set to the line driver/receiver 56 in the station circuit,
the station circuit being located in the equip~ent oabinet,
as mentioned.
Within a station circuit, the relay matrix is
arranged to handle up to ten lines per station in t~o groups
of five lines each (a twenty line station is handled by
grouping two station circuits together). Similarly, logic
circuits at both ends of the data pair are designed to operate~
with groups of five lines. Processing of data is carried out
on five lines at a time. If more than five lines are
required at one station, multi-group operation is involved
and two or more station circuits are coupled together. The
same two data wires and two speech wires are used b~tween
the station and the central equipment xegardless of the
number of lines appearing at that station, the control of
the spe~ch pair being exercised over the data pair by time
division methcds.
Each line selection button at each station set
is assigned to one trunk of line, at the time of installation.
This assignment is set on the programming panel in the control
equipment. The assignment of each button to a line is
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J. E~arsello~ti - 4
programmed by inserting a three-wire patch cord link between the station circuit and
the required trunk circ~Jit. Two of these wires are the voice pair (T ~ R) and the third
is the data control lead (H).
Each telephone line 70 from the CO or PBX is connected to a trunk circuit
72 where it is monitored for ringing voltage. In each trunk, logic and relay control
monitors and stores the status of the trunk and controls trunk conditioning features
such as hold, release, etc. From the trunk, connections are made to the programrning
panel (trunk side) as will be explained relative to Fig. 3.
Intercom links are regarded as variations of trunks in which the power for
the voice circuit is generated locally.
SYSTEM OPERATION
The system is controlled by the system control unit 80 which includes a
data processor 82 and a station address generator 84. The generator 84 sequentially
provides the address of each station, once per frame period (60 ms). The system
capacity is 96 lines, therefore each station is addressed for a 625 ,us period. This
period is called a sub-frame. Each station, together with the turnks assigned to that
station, is processed within its own sub-frame which re-occurs every 60 ms. This
timing produces a scanning rate of 16-2/3 Hz. The basic timing and sequence for the
system is shown in the reference patent cited.
The station circuit, when addressed, generates a "subscan" which provides a
sequential address to each of the five trunks assignable to the station being processed.
As they are addressed, the trunks transmit data which is representative of their status
to the system control unit.
J. sarsellotti - 4
1067633
The data indicates the trunk status such as trunk free,
busy, incoming call, held, etc.
When the sub~scan is complete, the system
control unit wi~l ~ave stored the status of each of ~he
five lines or trunks. From this status information, a code
is assem~led for serial transmission to the station set
data modem via the line driver/receiver within the station
circuit. The transmission of the coded data, which may be
in diphase form, is used to control the status display
and the tone caller or ringer in the station set.
The station set data modem transmits coded
data to the control equipment whenever an error-free
signal is recieved. The coded data is encoded serially
in diphase form. The coded data represents the status of
the line access buttons, miscellaneous control buttons
and the subset hookswitch.
The control e~uipment receives this coded data,
decodes it and compare~ the data to the trunk status
lnformation stored in the system control unit. From this
comparlson, control codes are a~sembled and sent to the
station and trunk circuits. The addressing is arranged so
that only the trunk to which the station is presently
connected (if any) will re~pond to the trunk control
code. Typical control codes to the trunks might cause cut-
through (to the station set), hold, release, change sacuri,ty
mode, etc. The most significant control code to the
station circait is used to switch the station set voice
pair to the required trunk, via the matrix within the station
circuit.
The entire control sequence is repeated during
every sub-frame, thus providing an update of the line
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J. Barsellotti - 4
status display on each station set every 60 ms. If the user wishes to select a line to
make an outgoing call or to answer an incoming call, he checks the status display, then
operates the required line access button. In the conventional manner, a free line will
have the associated line lamp extinguished, an incoming call will have its lamp lit by a
regular flash sequence, and a busy line will have a steadily lit lamp.
The identity of the requested line is sent to the control equipment over the
data pair during the next regular transmission interval. After checking the validity of
the llne request, the system control will switch the station set voice pair to the trunk
at the switching matrix and change the status of that trunk to busy. After the status
change indication, as each station is process, the status display will be updated to show
that the trunk is busy.
When a station set is connected to a trunk through the switching matrix, a
metallic path is completed from the station set speech pair to the CO/PBX line and
dialing can be accomplished in the normal manner.
In Figure 3, there can be seen a portion of the equipment cabinet 54
comprised in its lower half (not shown) of a plurality of slide-in printed circuit boards
50 containing the circuitry of the equipment cabinet shown in block form in Figure 1.
The upper half of the cabinet is faced with a structure to which is mounted the
programming panel 101 as shown in greater detail in Figure 2 which forms the substance
of the present invention.
The programming panel of Fig. 2 is used to determine which station will be
associated with a given line and which station or stations will operate under power
failure conditions in addition to various other optional features. Depending on the size
of an installation, one of the two types of programming panel will be used. For
systems with twelve stations or less, the programming panel of Fig. 2 is used. For
systems with up to 24 stations, a programming panel of essentially a double multiple of
the panel of Fig. 2 is used. Interconnections on the panel may be made by any suitable
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J. Barsellottl- 4
method, the preferred mode being three wire polarized plugs or by three individual
single wire plugs. Of these approaches, the use of three wire plugs is considered more
expedient and trouble free. The plugs mate with and engage horizontal pins which are
connected by suitable leads as shown in Fig. I to the operating components of the
system.
Except for the number of lines to be permitted access at a station,
programming panels whether twelve station or twenty-four station are laid out in the
same pattern as shown in Fig. 2. Two sizes may be used, a twelve station, six line size
or a twenty-four station, twelve line size, each size being configured in the pattern of
Fig. 2. The top portion, labeled "trunks" provides trunk appearances for six trunks for
each line appearance. Some of these trunk appearances are divided into two sections
labeled A and B. The A connections are identical to the connections for the remaining
lines, the B connections being reserved for special class of service (COS) functions.
The lower portion of the panels, labeled "Stations" provides one circuit
appearance for each station with access to up to ten lines per station. This part of the
board also contains a circuit for each station which may be used to program that
station for ringing and operation during power failure conditions. The lower section of
each board is reserved for the power fail and audible signalling options.
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J. sarsellotti - 4
10~i7633
Two or four groups of appearances in a single row are also
provided at the extreme bottom of the panel. These appear-
ances provide access to such special features as free line,
call~ng line-(sometimes called prime line pick-up), hold
mode, security mode. Spare appearances 1 through 6 and two
ground appearances are provided in each group. ~he spare
appearances can be used when patching from one circuit to
another with short leads. All appearances 1 through 6 in
each group are commoned in pairs. Methods of programming the
panel for various functions are outlined next.
Each appearance or block in Fig. 2 may be a pin
or may be a jack which receives the plugs and provides a
conne~tion to the circuit as seen in Fig. 1~
Line progr2mming includes assigning a line ttrunk
or intercom) to a specific key telephone station and a
specific lîne button on that telephone. This is accomplished
by connecting three wire patch cords between the desired
trunk and the desired station/button through the line appear-
ance on the programming panel.
If the station is to have restricted access to
the line, the trunk must be either trunk 1 or trunk 2, on
the 12-station system, or one of trunks 1 through 4 on the
24 station system. In either case, the patch cord mu~t be
connected to the B position of the trunk on the programming
panel. The B position gives access to Class of Service tCOS)
strapping on the trunk (line) card. When the B position is
used, th~ Class of Service (COS) strapping must be installed
on ~he trunk card.
The "A" po~ition does not permit restricted
servtce a~d is identical to the remaining trunk po~tion~
on the programming panel.
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7633
J. Barsellotti- 4
Each trunk can be patched to each station by patching from the desired
station/line button representation to the desired trunk appearance. Sample
connections are shown by conditions with circled indicator numbers. For example, if
non-restricted service from trunk I to station 1, line 3 is desired; a patch cord (three
conductor - T, H, R) would be installed between trunks IA and station I (connection 5
of Fig. 2). If, for example, restricted service is desired on station 2, line 3 on service
from trunk 2, the patch cord or strap should be installed from trunks 2B to stations 2, 4
for the three conductors T, H and R (connection 2 of Fig. 2). In this case, additional
strapping will be required on the trunk card for trunk 2.
Communications with stations in the system is possible during a power
failure condition by installing power fail strapping, provided the station is equipped
with a ringer; as a tone caller will not work. Each trunk can be connected to one
station during power failures. To connect the power failure feature, a strap is
completed from the pins designated PF TK to the LO pins of the desired station. For
example, to have station I ring when a call arrives on line I during a power failure, a
strap or connection is made from pins designated PF TKI to pins designated LO of
stations 1 with a three-conductor cord (connection 9 of Fig. 2).
If a 20 line subset is used, it is desirable, but not essential, that the two 10-
line groups be on the same station card (each card contains circuitry for two 10 line
stations3. To group two stations together to make one 20 lines station, three straps are
required, a three conductor
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~0~7633 J. Barsellotti - 4
cord is patched from pins designated Ll of one station to
pins LO of the second s~ation and a single conductor cord
is patched from pin M and AL pin of the first station to
pin M and pin AL of the second station. F~r example: if
it is desired to make stations 1 and 2 int~ one 20-line
station, the following straps should ~e installed: From
Station 1, line 1 Ll-Connect a three conductor cord to
pins designated station 2, LO, and from pins designating sta
tion l; M-Connect a single conductor cord to the pin designat-
ed station 2, M and from pins designated station l; AL-Connect
a single conductor cord to station 2, AL. A strap is also
required on the station card.
In this example, the patching positions for
station 2, buttons 1 through 10 would represent buttons
11 through 20 on the 20 line subset which is now considered
as sta~ion 1. Station 2 would be non-existent.
Features such as Hold, Security and Prime Line
Pick-up are programmed for the entire system in the system
control unit. However, limited deviation from the system
programming can be achieved via patching on the programming
panel. One or two stations on a twelve-station system or,
up to four stations o~ a twenty-four-station system, can
be programmed to operate in the opposite mode to all other
statlons in the system.
Each station patching position on the programming
panel has five pin9 labled "M". These can be patched, using
single condu~tor cords, to the pins at the bottcm of the
panel labled FL (Free Lance), CL (Calling Line), ~M (Hold
Mode) and~or S~ (Security Mode). When sueh a pat~h i9 made,
~he station involved will operate in the reverse mode to all
other (unpatched) stations.
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~06~7633
For ex~mple: Assume the control card to be
strapped to provide for manual hold, normally non-secure,
free line and calling line pick-up. In addition, assume
that station 1 has four cords patched from the station M
pins to HM, SM, FL and CL. In this case, station 1 will
have au_omatic hold, security operation and no free or calling
line pick ~auto pre-selection). This is the reverse of all
other (unpatched) stations. This patching can be applied
to reverse the operation of any or all these features.
All control, storage and transmission of data
i5 on a line basis with each line having pre-assigned time
intervals in th~ frame sequence, thus by physically associat-
ing a plurality of stations with respective lines by cross
connections at the pro~ramming panel, a fully flexible
interrelation of lines and stations is possible. In a like
manner, various special features can be provided to any desired
station or stations within the stated capabilities.
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