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Claims  |
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We claim:
1. A telephone communication system having an exchange and a plurality of
telephones connected to said exchange, wherein said exchange automatically
connects a first telephone to a second telephone when said first telephone
is being called by said second telephone and said first telephone responds
to the call, a method of automatically providing stored information to the
user of said second telephone, said method comprising the steps of:
storing information in said second telephone;
transmitting from a first telephone to said exchange an information
identifier wherein said information identifier is capable of identifying
information stored in said second telephone;
associating said information identifier with said first telephone;
storing in said exchange said information identifier and its association
with said first telephone;
controlling said exchange to transmit said information identifier to said
second telephone when said second telephone calls said first telephone;
and
providing said stored information to a user of said second telephone when
said information identifier is received by said second telephone.
2. The method of claim 1 wherein:
said step of storing information in said second telephone includes the step
of storing a plurality of messages for the user of said second telephone;
said step of storing said information identifier in said exchange includes
the step of storing at least one message identifier identifying a
respective message in said second telephone; and
said step of providing said stored information to said user includes the
step of providing to said user the message identified by said message
identifier.
3. The method of claim 1 wherein said step of storing information in said
second telephone includes the steps of previously storing said information
in said exchange and transmitting said information to said second
telephone from said exchange.
4. The method of claim 1 further including the step of providing a display
on said second telephone for display of said stored information in
response to the receipt of said message identifier.
5. The method of claim 1 wherein:
said step of storing information in said second telephone includes the step
of storing at least one message having a fixed part and an undetermined
changeable part;
said step of transmitting from said first telephone includes the step of
transmitting to said exchange said changeable part;
said step of storing in said exchange includes the step of storing said
changeable part in said exchange;
said step of controlling said exchange includes the step of transmitting
said changeable part to said second telephone when said second telephone
calls said first telephone; and
said step of providing said stored information includes the step of
providing said message to the user of said second telephone when said
information identifier is received by said second telephone, wherein said
changeable part is provided along with said fixed part of said message.
6. A telephone communication system having an exchange and a plurality of
telephones connected to said exchange, wherein said exchange automatically
connects a called telephone to a calling telephone when said called
telephone is being called by said calling telephone, a method of
automatically providing stored information to a user of said calling
telephone, said method comprising the steps of:
storing information in said calling telephone;
providing said exchange with an information identifier identifying the
information stored in said calling telephone;
providing said exchange with data associating said information identifier
with said called telephone;
storing in said exchange said information identifier and its association
with said called telephone;
controlling said exchange to transmit said information identifier to said
calling telephone when said calling telephone calls said called telephone;
and
providing said stored information to the user of said calling telephone
when said information identifier is received by said calling telephone.
7. The method of claim 6 wherein said step of:
storing information in said calling telephone includes the step of storing
a plurality of messages for the user of said calling telephone; and
said step of providing said exchange with an information identifier
includes the step of providing at least one message identifier identifying
a respective message in said calling telephone.
8. The method of claim 6 wherein said step of storing information in said
calling telephone includes the step of transmitting previously stored
information to said calling telephone from said exchange.
9. The method of claim 6 further including the step providing a display on
said calling telephone for display of said stored information.
10. The method of claim 6 wherein:
said step of storing information in said calling telephone includes the
step of storing at least one message capable of having a fixed part and a
changeable part;
said step of providing said exchange with an information identifier
includes providing said exchange with data indicative of a changeable
part;
said step of storing in said exchange includes the step of storing said
changeable part in said exchange;
said step of controlling said exchange includes the step of transmitting
said changeable part to said calling telephone when said calling telephone
calls said called telephone; and
said step of providing said stored information to the user includes the
step of providing said message to the user of said calling telephone when
said information identifier is received by said calling telephone, wherein
said changeable part is provided along with said fixed part of said
message.
11. A message communication method for use in an electronic switching
system having an exchange and a plurality of telephone terminals connected
to said exchange, said method comprising the steps of:
presetting at least one message in at least one of said telephone terminals
to be called and transmitting data including a message identifier
corresponding to said preset message to said exchange;
receiving said data in said exchange and storing said message identifier in
relation to the telephone terminal from which said data was transmitted;
determining the operating status of a called telephone terminal;
transmitting said data to a calling telephone terminal when said called
terminal has a preset message;
receiving said data transmitted from said exchange in said calling
telephone terminal;
searching for a message corresponding to said message identifier in said
calling terminal and displaying the contents of said searched message at
said calling terminal.
12. A message communication method according to claim 11 further comprising
the step of transmitting a plurality of message identifications and
respective messages from said exchange to said telephone terminals
connected to said exchange prior to preset of at least one message in at
least one of said telephone terminals to be called.
13. A message communication method according to claim 11 wherein said step
of determining the operating status of a called telephone includes the
step of recognizing whether a calling telephone terminal has a display and
transmitting a voice signal corresponding to a message when said calling
telephone terminal does not have a display.
14. A message communication method according to claim 11 wherein at least
one of said message includes a changeable portion and said message
identifier corresponding to said changeable portion, said data including
said changeable portion.
15. A message communication method for use in an electronic switching
system, having an exchange and a plurality of telephone terminals
connected to said exchange, said method comprising the steps of:
setting at least one message identifier and respective message in one or
more of said telephone terminals;
transmitting data including a message identifier corresponding to said set
message from a calling telephone terminal to said exchange;
receiving said data in said exchange and transmitting said received data to
particular telephone terminals when a called terminal is busy;
receiving said data transmitted from said exchange in said particular
telephone terminals; and
displaying in said particular telephone terminals the contents of said set
message in response to said message identifier included in said received
data.
16. A message communication method according to claim 15 further comprising
the step of transmitting a plurality of message identifiers and respective
messages from said exchange to said telephone terminals for storage
thereof in said telephone terminals.
17. A message communication method according to claim 15 wherein at least
one of said messages comprises a fixed part and a changeable part, said
message identifier corresponding to said fixed part and said data
including said changeable part.
18. A message communication system in an electronic switching system having
an exchange and a plurality of telephone terminals connected to said
exchange, comprising:
first storage means in said telephone terminals for storing a plurality of
message identifiers and respective messages;
presetting means in said telephone terminals, for presetting at least one
of said messages;
first transceiver means provided in said telephone terminals, for
transmitting to said exchange and receiving therefrom data including
message identifiers;
display means provided in said telephone terminals for displaying the
contents of a message;
first control means operatingly connected to said first storage means, said
presetting means, said first transceiver means and said display means for
controlling said first transceiver means to transmit said data when a
message is present in said presetting means, and searching said first
storage means to find the message corresponding to a message identifier
when transmitted from said exchange and received by said first transceiver
means, and controlling said display means to display the contents of at
least said searched message;
second storage means provided in said exchange for storing status
information associated with said telephone terminals;
second transceiver means provided in said exchange for transmitting to said
telephone terminals and receiving therefrom said data;
second control means, operatingly connected to said second storage means
and said second transceiver means, for storing message identifiers with
said status information in said second storing means when received by said
second transceiver means and controlling said second transceiver means to
transmit said data to a calling telephone terminal when the telephone
terminal having a preset message is called.
19. A message communication system according to claim 18 further comprising
memory means provided in said exchange for storing a plurality of message
identifier and respective messages, wherein said second control means
further controlling said second transceiver means to transmit said
plurality of message identifiers and respective messages to all of said
telephone terminals provided with said first memory means for reception
thereof.
20. A message communication system according to claim 18 further comprising
voice synthesizing means for generating voice signal corresponding to a
message, said second control means includes recognizing means for
recognizing whether a calling telephone terminal has a display, said
second control means further controlling said synthesizing means to
generate said voice signal when said calling telephone terminal does not
have a display.
21. A message communication system according to claim 18 wherein at least
one of said messages includes a changeable portion and an unchangeable
portion, said message identifier corresponding to said unchangeable
portion and said data including said changeable portion.
22. A message communication system in an electronic switching system having
an exchange and a plurality of telephone terminals connected to said
exchange, said message communication system comprising:
first storage means in said telephone terminals for storing a plurality of
message identifiers and messages;
setting means in said telephone terminal for setting at least one message;
first transceiver means provided in said telephone terminals for
transmitting to said exchange and receiving therefrom data including said
set message;
display means provided in said telephone terminals for displaying the
contents of said set message;
first control means for operatingly connected to said first storage means,
said setting means, said first transceiver means and said display means
for controlling said transceiver means to transmit said data when a
message is set in said setting means, and searching said first storage
means to find the message corresponding to a message identifier when
transmitted from said exchange and received by said first transceiver
means, and controlling said display means to display the contents of a set
message;
second transceiver means provided in said exchange for transmitting to a
telephone terminal and receiving therefrom said data;
second control means operatingly connected to said second transceiver means
for controlling said second transceiver means to transmit said data
transmitted from a calling telephone terminal to a called telephone
terminal when said called telephone terminal is busy.
23. A message communication system according to claim 22 further comprising
memory means provided in said exchange for storing a plurality of message
identifiers and respective messages, wherein said second control means
further controlling said second transceiver means to transmit said
plurality of message identifiers and respective messages to all telephone
terminals provided with said first memory means for reception thereof.
24. A message communication system according to claim 22 wherein, at least
one of said messages includes a changeable portion and a unchangeable
portion, said message identifier corresponding to said unchangeable
portion and said data including said changeable portion.
25. A message communication method for use in an electronic switching
system having an exchange and a plurality of telephone terminals connected
to said exchange, said method comprising the steps of:
storing a plurality of message identifiers and respective messages in said
telephone terminals;
setting a message in a calling telephone terminal when the then called
telephone terminal is busy;
transmitting data including a message identifier corresponding to said set
message from said calling telephone terminal to said exchange;
receiving said data in said exchange and transmitting said received data to
said busy called telephone terminal;
receiving said data transmitted from said exchange in said busy called
telephone terminal; and
displaying in said busy called telephone terminal the contents of one of
said stored messages in response to said message identifier included in
said received data.
26. A message communication method according to claim 25 further comprising
the step of transmitting a plurality of message identifiers and respective
messages from said exchange to said telephone terminals for storage
thereof in said telephone terminals.
27. A message communication method according to claim 25 wherein at least
one of said messages comprises a fixed part and a changeable part, said
message identifier corresponding to said fixed part and said data
including said changeable part. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
The present invention generally relates to the field of telecommunications
and more particularly, is directed to a method and apparatus for
automatically transmitting a message to a telephone terminal.
Over the last several years, there has been a marked increase in the level
of sophistication and complexity of electronic telephone exchange systems.
In addition, telephone sets have been developed which are far superior in
terms of capability to those previously known in the art. Such functions
are touch-tone and multi-function telephone sets are not commonplace and
are continuing to be improved. Present day telephone sets and electronic
exchange systems represent a substantial improvement over such devices
known in the prior art. There is still a need, however, for further
improvement. For example, it is not possible to make a telephone call to a
telephone set which is presently being used. The calling party merely
receives a busy signal alerting him that the telephone set which he is
trying to reach is presently in use. In matters of great urgency, it is
necessary to be able to communicate with a telephone set even though it
may be in use. Moreover, in routine situations, it is often convenient to
pass a message to the user of a telephone set such that the user may
receive important information timely. In telephone sets known in the prior
art, such a feature is not available.
Present-day telephone sets are further deficient in that they provide no
means of communicating to a calling party that the person he wishes to
reach is out of the office or away from his telephone for an extended
period of time. Of course such devices as automatic telephone answering
machines are available. However, such machines are rather expensive and
are prone to the user forgetting to turn them on prior to leaving his
office or home. Accordingly, there is a need in the art to provide a
telephone set which can automatically inform the calling party that the
person whom he wishes to reach is not presently available. Moreover, such
telephone sets should have the capability of ease of use while at the same
time providing the user with substantial flexibility in programming
messages for automatic transmission to a calling party. As mentioned
above, automatic answering machines are presently available and do provide
a useful service. Such service, however, is limited for the
above-mentioned reasons and also for the reason that they usually cannot
be set up to provide more than one or two messages for playback to a
calling party. Usually, such messages cannot readily be changed, thereby,
causing the telephone user to always rely on a somewhat general and
nonspecific message. Such messages usually provide little, if any,
accurate information as to the present whereabouts or expected time of
return of the user.
Though voice store and forward systems are known in the art, such systems
are rather complicated and expensive to implement. These systems usually
include a voice signal memory which records the voice of the calling party
for playback to the person being called at some predetermined time. The
deficiencies in such a system are apparent. For example, there is usually
no way to know the ideal time which the recorded voice signal should be
played back to the called party. Moreover, the amount of memory required
to store voice signals is substantial, thereby greatly reducing the number
of messages that can be stored in any given system.
Accordingly, there is a great need in the art for a system which can be
used to efficiently, rapidly and reliably transmit a message to a
telephone when the telephone is in use or when the telephone cannot be
answered.
SUMMARY OF THE INVENTION
It is, therefore, the overall object of the present invention to provide a
telephone message communications system which is far superior to such
systems known in the prior art.
It is another object of the present invention to provide a telephone
message communication system for use in conjunction with a telephone
exchange which performs conventional exchange functions.
It is another object of the present invention to provide a telephone
message system for use with a telephone exchange which permits a plurality
of messages of different types to be automatically transmitted to a called
or calling telephone.
It is a still further object of the present invention to provide a
telephone message system which permits a message to be transmitted to a
telephone even though the telephone is in use.
It is a still further object of the present invention to provide a
telephone message system which automatically responds to a calling
telephone with information concerning the status of the telephone being
called.
These and other objects of the present invention are achieved by providing
a telephone message system wherein each telephone includes a central
processing unit and a plurality of input keys which may be actuated to
access one or more stored messages in the telephone. Each message may
include a fixed part and a changeable part. One example of such a message
is "Out of office till .sub.---- :.sub.----." The changeable portion of
the message is represented by dashes and would by the time of day, as for
example, "03:00". Thus, when the particular telephone having such a
message is called, the message is automatically transmitted to the calling
telephone for display on the calling telephone. Thus, the caller would
know immediately that the person whom he is trying to reach will be out of
the office until 3:00 o'clock. Such a feature avoids the problem of the
calling party having to leave a message and the attendant problem of the
message not being communicated to the person being called. In the system
of the present invention, the calling party will know that he should call
back at 3:00 o'clock. Thus, the likelihood that the calling party will
reach the intended party is greatly increased.
In accordance with the present invention, when a telephone user wishes to
preset a message for automatic transmission to a calling party, he selects
the message from a plurality of messages and then transmits to the central
exchange an identification code which identifies the selected message. The
identification code is stored in the exhange. In addition, if the message
includes a changeable part, the changeable data is also sent to the
exchange and stored along with the identification code. When the exchange
receives a call which is destined for the telephone from which the
identification code came, the call is intercepted and the exchange
automatically transmits the identification code and any changeable
information to the calling telephone. The calling telephone has a
corresponding table of messages, one of which matches the identification
code. The identified message is then automatically displayed on the
calling telephone.
In another embodiment of the present invention, a message may be
transmitted from one telephone to another telephone even though the
destination telephone is presently busy. Such a feature is of great
convenience and insures that a telephone user will always receive
important messages timely.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a telephone message communication system in
accordance with the present invention.
FIG. 2 is an illustration of a 2-line bi-directional burst transfer method
of transmitting information.
FIG. 3 is an illustration of the signal format used in the burst transfer
method shown in FIG. 2.
FIG. 4 is an illustration of a multi-bit control signal used in the present
invention.
FIG. 5 is an illustration of an NRZ signal and a DP signal train.
FIG. 6 is a block diagram of one embodiment of a telephone terminal for use
with the telephone message communication system shown in FIG. 1.
FIG. 7 is a circuit diagram of hybrid circuit 224 shown in FIG. 6.
FIG. 8 is a top view of the telephone terminal illustrated in FIG. 6.
FIG. 9 is a block diagram of line card 3 shown in FIG. 1.
FIGS. 10a and 10b are flow charts illustrating the operation of CPU 251 in
the telephone terminal shown in FIG. 6 when a key on the terminal is
activated.
FIG. 11 is a flow chart illustrating the operation of CPU 10 in the
telephone message communication system shown in FIG. 1 when an incoming
signal is received.
FIG. 12 is a flow chart illustrating the operation of CPU 10 in the
telephone message communication system shown in FIG. 1 when an address
signal designating a called party is received.
FIGS. 13a and 13b are flow charts illustrating the operation of CPU 251 in
the telephone terminal shown in FIG. 6 when an incoming signal is
received.
FIG. 14 is an illustration of the data format used when the telephone
terminal shown in FIG. 6 is in a preset message mode.
FIG. 15 is an illustration of customer data and telephone message related
data which corresponds to respective ports of telephone exchange 1 shown
in FIG. 1.
FIG. 16 is another illustration of the operation of the telephone terminal
shown in FIG. 1.
FIG. 17 is an example of the display of the functions assigned to the soft
keys in the telephone terminal shown in FIG. 6.
FIG. 18 is an illustration of the data format used when the telephone
terminal shown in FIG. 6 is in the real time message mode.
FIG. 19 is a flow chart illustrating the operation of CPU 10 for
controlling the telephone exchange shown in FIG. 1.
FIG. 20 is an illustration of the format of the signal used to send message
related data from the exchange shown in FIG. 1 to a telephone terminal.
FIG. 21 is a flow chart illustrating the operation of CPU 10 of the
exchange shown in FIG. 1 when checking the status of the various telephone
terminals connected to the exchange and updating telephone user related
information.
FIG. 22 is an illustration of the format of control signals used during
formation of a telephone load map.
FIG. 23 is an illustration of the procedure used for inputting a message
from the data terminal shown in FIG. 1 in accordance with the present
invention.
FIG. 24 is a block diagram of a telephone message communication system in
accordance with another embodiment of the present invention.
FIG. 25 illustrates the construction of voice synthesis circuit 402 shown
in FIG. 24.
FIG. 26 illustrates the process used by voice synthesis circuit 402 shown
in FIG. 24 to obtain PCM voice data from message data.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A preferred embodiment of the telephone message communication system in
accordance with the present invention will be described below with
reference to the annexed drawings.
With reference to FIG. 1, one embodiment of the present invention comprises
exchange 1 and a plurality of telephone terminals 2, each having a visual
display. Each of telephone terminals 2 may be used to communicate with any
other terminals connected to exchange 1.
As shown in FIG. 1, exchange 1 includes a plurality of line card 3 through
which telephone terminals 2 are connected to exchange 1. As will be
described below, line card 3 and telephone terminal 2 are connected to
each other by a 2-line bi-directional bus using a burst transfer
technique. A plurality of telephone terminals 2 may be connected to a
common line card 3 as shown in FIG. 1.
Pulse coded modulation (PCM) buses PH 31 and PH 32 connect line card 3 to
time switch circuit 4. Trunk card 5, tone circuit 6 and conference circuit
7 are also connected to switch circuit 4 by PCM buses PH50, PH60 and PH70,
respectively. Each PCM buss carries PCM audio signals and data signals.
Time switch circuit 4 is adapted for multiplexing the signals on PCM
busses PH31, PH32, PH50, PH60 and PH70.
Trunk card 5 has wires MW and leased circuit wires LC connected to it.
These wires are used to connect exchange 1 to other remote exchanges. Tone
circuit 6 is adapted to generate various tones, such as busy signal and a
dial tone for transmission to telephone terminal 2 and main wires MW.
These tones are supplied as digital signals from circuit 6. Conference
circuit 7 provides telephone conference call capability to telephone
terminals 2.
The operations of line card 3, time switch circuit 4, trunk card 5, tone
circuit 6 and conference circuit 7 are based on reference clocks supplied
from clock generator 8. Line card 3, trunk card 5, one circuit 6 and
conference circuit 7 are also connected to I/O interface 9 by data buss DH
and PCM frame signal line FS. CPU 10, floppy disk 11, memory 12 and
input/output circuit 13 are connected to I/O interface 9 by buss CB1.
Floppy disk 11 stores various data, as well as an operating system program
which is executed by CPU 10 to control exchange 1. The data and operating
system stored in floppy disk 11 may be loaded into memory 12 when exchange
1 is first activated.
Data terminal 14 is connected to input/output circuit 13 and is used mainly
to input system data and for system maintenance. System data includes such
data as the design and capability of telephone terminal 2 where terminal 2
is a multi-function terminal, the various functions assigned to each
telephone function key on terminal 2 and other information specific to
respective telephone terminals. Data terminal 14 may also be used to enter
messages in accordance with the present invention.
As stated above, line card 3 and telephone terminal 2 are interconnected by
a 2-line bi-directional buss. Data signals are exchanged using a bust
transfer technique similar in operation to a ping-pong ball being hit back
and forth across a ping-pong table. As shown in FIG. 2, signals of a
predetermined format are transmitted in a burst manner from line card 3 to
telephone terminal 2. In return, signals of a predetermined format are
transferred to a burst manner from telephone terminal 2 to line card 3.
This signal exchange is usually conducted within 125 micro seconds.
The signal format used for the signals shown in FIG. 2 consists of a
plurality of frames; each having 12 digital bits as shown in FIG. 3. The
leading bit F is a frame synchronization bit. The next 8 bits V are
alloted for digitized audio signals. Bit D is a data bit which is followed
by a control bit C and a parity bit P. Since each frame can be transmitted
within 125 micro-seconds, bits V, which contain a digitized audio signal,
has a transfer rate of 64 kbps.
Data bit D is used to transfer data between a data terminal connected to
line card 3. When there is no need for a digitized audio transer, audio
bits V can also be used as data bits D. Control bit C is provided for the
purpose of controlling telephone terminal 2. A complete control signal is
comprised of 12 bits as shown in FIG. 4. Thus, a control signal is formed
by accumulating 12 control bits C from 12 successive frames having the
format shown in FIG. 3. Parity bit P serves as a parity check.
As discussed above, signal transfers between telephone terminal 2 and line
card 3 are via a 2-line bi-directional buss using a burst transfer
technique. Each signal is di-phase encoded where a signal level change is
synchronized with a reference clock. In response to a logic "1" signal,
the level of the di-phase signal remains constant during the same clock
period. However, in response to a logic "0" signal, the level of the
di-phase signal may change within the same clock period. FIGS. 5a and 5b
show practical examples of NRZ and di-phase (DP) signal trains. Such
signals will be discussed further below.
With reference to FIG. 6, the construction of telephone terminal 2 will be
explained. For purposes of explanation only, it is assumed that data
terminal 21 is connected to telephone terminal 2. Telephone terminal 2
includes burst transfer module 22, voice module 23, operating module 24,
processing module 25 and time reference module 26.
Burst transfer module 22 includes transmitting frame register 221, parity
adding circuit 22, NRZ/DP converter 22, hybrid circuit 224, DP/NRZ
converter 225, receiving frame register 226 and two 12-bit shift registers
227 and 228. Burst transfer module 22 is adapted to exchange signals with
exchange 1 shown in FIG. 1 and to exchange digital data with voice module
23. Burst transfer module 22 also exchanges digital data with processing
module 25 and data terminal 21.
Voice module 23 includes handset 231, speaker 232, coder/decoder 233,
amplifier 234 and I/O 235. Voice module 23 converts a digitized audio
signal to an anologue voice signal and viceversa. Operating module 24
includes liquid crystal display (LCD) 241, soft keys 242A-242G, function
keys 243A, 244D, dial pad 245, light emitting diodes (LEDs) 246A-246G, I/O
247, LED controler 248 and LCD controler 249. Operating module 24 provides
an electronic interface between uses of telephone terminal 2 and
processing module 25. Processing module 25 includes CPU 251, ROM 252, RAM
253 and common buss 254. Voice module 23, operating module 24 and burst
transfer module 22 are also coupled to CPU 251 via buss 254. Processing
module 25 is also adapted to control the operation of the above described
modules within terminal 2. As also shown in FIGS. 6, time reference module
26 includes frame detecting circuit 261 and timing generating circuit 262.
Voice module 23 is adapted to convert the PCM voice data received in
digitized form from burst transfer module 22 into analogue voice signals
by means of coder/decoder 233 in response to a timing signal T.sub.2 from
time reference module 26. The resulting analogue voice signals are
transferred through amplifier 234 to handset 231 or to speaker 232 as
audible sound. Coder/decoder 233 is a PCM coder/decoder having both coding
and decoding functions. Control of coder/decoder 233 and amplifier 234 by
CPU 251 is conducted through common buss 254 and I/O 235.
The incoming analogue voice signals from handset 231 is delivered through
amplifier 234 to encoder/decoder 233. The analogue signals are converted
to digital form in encoder/decoder 233 and are then provided to
transmitting frame register 221 of burst transfer module 22. Transmitting
frame register 221 has a portion V for the digitized voice signal, a
portion D for the data signal and a portion C for the control signal. The
output of coder/decoder 233 is provided to voice portion V, the output of
data terminal 21 is provided to data portion D through I/O 211 and the
output of shift register 228 is provided to control signal portion C. The
output from transmitting frame register 221 is provided to parity bit
adding circuit 222, the output of which is sent to NRZ/DP converter 223
and is then delivered to hybrid circuit 224 for transmission to exchange 1
shown in FIG. 1. The above described elements constitute the transmitting
portion of burst transfer module 22.
In the receiving portion of burst transfer module 22 incoming signals from
exchange 1 are coupled to hybrid circuit 224. The output from hybrid
circuit 224 is supplied to DP/NRZ converter 225. The signals are supplied
from exchange 1 to DP/NRZ converter 225 as a succession of frames in
accordance with the format shown in FIG. 3. The ouptut from DP/NRZ
converter 225 is supplied to receiving frame register 226. As in
transmitting frame register 221, receiving frame register 226 has a
portion V for the voice signal, a portion D for the data signal and a
portion C for the control signal. These portions comprise eight digital
bits, a first single digital bit and a second single digital bit,
respectively, the frame bit and parity bit having been removed from each
frame.
The data in voice portion V in receiving frame register 226 constitutes an
input for coder/decoder 233. Similarly, the data in data portion D is
supplied to data terminal 21 through I/O 211, an RS 232C port. The data in
control portion C is supplied to 12-bit shift register 227.
Transmitting frame register 221 operates in the following manner. An 8-bit
PCM digital voice signal from coder/decoder 233 is temporarily stored in
voice signal portion V of transmitting frame register 221. CPU 251
transmits over common buss 254 control data consisting of a plurality of
12-bit units. This control data is temporarily stored in control signal
portion C of 12-bit shift register 228. Shift register 228 supplies the
data in a bit-by-bit fashion to control signal portion C of transmitting
frame register 221. Each bit of the control data is transmitted from
12-bit shift register 228 once every 125 micro seconds. This rate is
controlled by timing signal T.sub.1 from time reference module 26. As
mentioned above, the data from data terminal 21 is stored in data portion
D of transmitting frame register 221 through I/O 211. The transmission of
data from I/O 211 is also controlled by a timing signal T.sub.1.
After preparation of the 10 bits of data in transmitting frame register 221
as described above, the data is sent to parity adding circuit 222 in
accordance with timing signal T.sub.31 from time reference module 26 where
frame synchronizing bit F and parity bit P are added to the data bits.
This format is the same as that shown in FIG. 3. The data is ouptut from
transmitting frame register 221 with a 100% duty cycle ratio and has the
same form as a Non-Return-To-Zero (NRZ) signal. This NRZ signal is
subjected to di-phase coding by NRZ/DP converter 223. Thereafter the
signal is sent to hybrid circuit 224 for transmission to exchange 1.
In the signal receiving mode, the di-phase coded signal from exchange 1 is
received by hybrid circuit 224 and is converted into an NRZ signal train
by DP/NRZ converter 225. As described above, the incoming signal is formed
of 12 digital bits in accordance with the format shown in FIG. 3. The data
in the second to ninth bits from the starting end are stored in voice
portion V of receiving frame register 226. The data in the tenth and
eleventh bits are stored in data portion D and control signal portion C,
respectively.
The data in voice signal portion V is supplied to coder/decoder 233 and is
converted into an audible sound as afore described. The data in data
portion D is transferred to data terminal 21 through I/O 211. The data in
control signal portion C is sent to 12-bit shift register 227 and after 12
control signal bits are accumulated, the complete control data signal is
transmitted to CPU 251 through common buss 254.
The key input information from dial pad 245, soft keys 242A-242G, function
keys 243A-244D of operating module 24 are transmitted to CPU 251 through
common buss 254. Upon rceipt of the information associated with function
keys 243A-244D, CPU 251 executes a program stored in ROM 252 to control
LED controller 248 which activates selected LEDs from among LEDs
246A-246G.
With reference to FIG. 7, the operation of NRZ/DP converter 223, hybrid
circuit 224 and DP/NRZ converter 225, will be described. Converters 223
and 224 are electrically connected to exchange 1 shown in FIG. 1 through
hybrid coil 244C. The converters are respectively comprised of a
transmitting section 229T which includes NRZ/DP converter 223 and a
receiving section 229R which includes DP/NRZ converter 225. In this
arrangement, the signal from exchange 1 is received as di-phase coded
digital data in the format shown in FIG. 3. The signal is then supplied to
DP/NRZ converter 225 through operational amplifier circuits 224B for
conversion to a NRZ coded signal. The NRZ signal is supplied to frame
register 226 as above described. On the other hand, digital data signals
of the format shown in FIG. 3 for transmission to exchange 1 are supplied
to NRZ/DP converter 223 for conversion from NRZ coding to di-phase coding.
The di-phase coded signals are then transmitted to exchange 1 via hybrid
coil 224C.
The operation of time reference module 26 shown in FIG. 6 will now be
described. In this embodiment of the invention, timing signals for the
operation of the telephone terminal are derived from time reference module
26. More specifically, the frame synchronization bit is detected from the
signal received by frame detecting circuit 261. The various timing signals
are generated in synchronism with the time of detection. Timing signals
T.sub.1 -T.sub.5 are generated in accordance with the clock signals from a
clock generator (not shown) in timing generating circuit 262. Timing
signals T.sub.1, T.sub.2, T.sub.31, T.sub.32,T.sub.41, T.sub.42, and
T.sub.5 are clock signals having frequencies of 8 kHz, 64 kHz, 256 kHz,
512 kHz and 2 MHz, respectively. Timing signals T.sub.31 and T.sub.41 are
generated only during the period of a burst transmission and timing
signals T.sub.32 and T.sub.42 are generated only during the period of a
burst reception.
As can be seen from FIG. 8, and as explained above, the telephone terminal
includes LCD 241 and soft keys 242A-242G which are located adjacent LCD
241. The function of soft keys 242A-242G are assigned in accordance with
the operating state of the telephone terminal. The display area of LCD 241
is divided into a plurality of display portions each of which displays a
respective function assigned to the soft keys.
A first set of function keys 243A-243G are provided along with soft keys
242A-242G. Various functions may be assigned to function keys 243A-243G
and LEDs 246A-246G are provided to indicate the status of these functions
keys. A second set of function keys 244A-244D are also provided in
addition to function keys 243A-243G. Fixed functions, such as auto-dialing
and automatic re-dialing are preassigned to the function keys.
Dial pad 102 is provided on the upper central portion of the housing of the
telephone terminal. A speaker 232 and handset 231 are provided on the left
side of the housing. Handset 232 is connected to the inner circuitry of
the telephone terminal through handset cord HC. The telephone terminal is
connected to exchange 1 (line card 3) shown in FIG. 1 through line EX.
The operation of line card 3 shown in FIG. 1 will be described with
reference to FIG. 9. Line card 3 includes burst transfer module 31,
processing module 32, interface module 33 and time reference module 34. A
separate burst transfer module 31, interface module 33 and time reference
module 34 is provided for each telephone terminal which is connected to
line card 3.
Burst transfer module 31 includes transmitting frame register 311, parity
adding circuit 312, transmitting/receiving circuit 313, hybrid circuit
314, receiving frame register 315 and two 12-bit shift registers 316 and
317. Processing module 32 includes CPU 321, memory 322 having ROM and RAM,
common buss 323 and I/O 324. Interface module 33 includes demultiplexer
331 and multiplexer 332. Time controlling module 34 includes address
register 341, counter 342, time generating circuit 343, comparater 344 and
frame detecting circuit 345.
Hybrid circuit 314 and transmitting/receiving circitt 313 in burst transfer
module 31 have the same constructions and operate in the same manner as
the corresponding circuits shown in FIG. 7. Thus, these circuits are
adapted for receiving signals from exchange 1, converting the received
signal into NRZ signals and converting the NRZ signals into di-phase (DP)
signals for transmission to exchange 1.
In the receiving portion of transmitting/receiving circuit 313, incoming
signals from exchange 1, after conversion to NRZ signals, are provided to
receiving frame register 315 in accordance with timing signal T.sub.32
from reference module 34. At this time, the data in the second to ninth
bits as counted from frame synchronization bit F are stored in voice
signal portion V. The data in the tenth bit is stored in data portion D
while the data on the eleventh bit is stored in control signal portion C.
Multiplexer 332 delivers the contents of voice signal portion V and data
portion D to the PCM buss in accordance with timing signal T.sub.11 from
time reference module 34. The PCM buss is connected to the switch circuit
4 shown in FIG. 1 as aforedescribed. The control signal stored in control
signal portion V of receiving frame register 315 is accummulated in 12-bit
shift register 316 bit by bit every time timing signal T.sub.12 is
applied. The 12 bits thus accummulated forms a control signal which is
then transferred to CPU 321 through buss 323. CPU 321 reads this signal
through a predetermined process in accordance with the contents of memory
322 and delivers the same to the data through I/O 324 as required. The
data delivered to the data buss is sent to CPU 10 in exchange 1 where it
is processed in a predetermined manner.
The transfer of signals from the telephone terminal to exchange 1 via line
card 3 is conducted in the manner described above. The transfer of signals
from exchange 1 to the telephone terminal is conducted in the following
manner. PCM voice data and data | | |
