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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to an apparatus for providing a
printed record of data transmitted over common carrier communication lines
from a pushbutton telephone. More particularly, the present invention
relates to a printer/recorder apparatus adapted to make a permanent record
of numeric information transmitted from a standard pushbutton telephone.
2. Background of the Prior Art
Facsimile, teletype and telescribe communications systems have been
developed for transmitting orders from a plurality of outlying
order-initiating stations to a central depot. Many of these systems use
audio tones within the frequency range of audio tones used in a standard
Touch Tone.TM. telephone because this regime affords compatability with
common carrier communication lines. All prior art systems, however,
require complex apparatus to encode information at a transmitting station
and further require complex and expensive equipment to decode transmitted
information at a receiving depot. Because of these limitations, such
systems are used only by large corporations and have heretofore been
economically unavailable to the general small businessman who must order
his goods from a central supply point.
The prior art also teaches use of a standard 12-button Touch Tone.TM.
telephone to transmit information over common carrier lines to a central
computing facility. This art uses a telephone as a remote data terminal.
It is also well known to provide a printer/recording apparatus located at
an unattended telephone receiving station to record alphanumeric data from
a pushbutton telephone encoded according to an arbitrary coding scheme.
All prior art known to the applicant requires either a sophisticated
computing system at the receiving station or use of a complex arbitrary
coding scheme to allow the transmission of alphanumeric data from the
Touch Tone.TM. pad of the telephone. The computer system is too expensive
to be used by most small businesses and any system that uses an encoding
scheme is too complex and prone to error to be used by lay operators.
Because of these deficiencies in the prior art, no inexpensive, simple to
operate, printed record order system had been developed that can be used
by untrained operators of small businesses on a routine basis.
In virtually all situations where a plurality of outlying users place
orders with a central supply depot, it is desirable to queue the orders
and to provide a permanent indication of the time the order was placed so
the supply depot can fill orders within a reasonable time and on a
first-come, first-serve basis.
Prior to the development of electronic telephone switching systems, several
systems were developed for providing a printed record or other visible
indication at the called station of the number of a calling party or other
information transmitted by the calling party. These early devices required
special equipment at the telephone company's central station in addition
to recording and display equipment at the receiving station. The prior art
also reflects a number of specialized telephone data transmission and
control systems that use specialized input and output devices. These
include telegraph, facsimile and teletypewriter systems.
In Scantlin, U.S. Pat. No. 3,371,172, a communications system is disclosed
utilizing a pushbutton telephone for transmission of pulse trains
containing digital data to a called party's location. There a tone decoder
is employed to convert tone trains into electrical impulses for
controlling the operation of an information unit. Morgan, U.S. Pat. No.
3,515,814, describes how a pushbutton telephone may be used as the data
communications link between an input terminal and a remote computer.
Goldstein, U.S. Pat. No. 3,557,311, shows an input keyboard coupled to an
associated printer for transmission of alphanumeric data from a pushbutton
telephone and recording at the calling party's station of the transmitted
message. Finally, Flanagan et al, U.S. Pat. No. 3,675,513, describes a
pushbutton telephone transmission system comprising a modified typewriter
coupled to a receiving station for providing a permanent record of data
transmitted by the user at the sending station. The message may be input
to the system either through a modified typewriter for automatically
coding messages to be sent over the telephone or, alternatively, direct
inputting of the message through manual actuation of the dial buttons on a
pushbutton telephone set.
The closest prior art known to the inventor of the present invention is
U.S. Pat. No. 3,870,821, which was issued Mar. 11, 1975 to Steury. Steury
teaches a printer/recorder apparatus for use with a 12 or 16-key
pushbutton telephone communication system wherein a relatively complex
arbitrary code comprising two code groups, each group having a plurality
of sub-groups, is used to transmit alphanumeric information to a remote
unattended printer.
SUMMARY OF THE PRESENT INVENTION
The present invention is an improved apparatus for making a printed record
automatically at a central station of the general type described in the
aforementioned Steury patent. In lieu of the arbitrary and complex coding
system required by Steury, the present invention includes an apparatus
electrically connected to the phone lines for automatically detecting and
receiving a message from any Touch Tone.TM. telephone and further
discloses means for logging the time and numeric data transmitted by the
remote telephone. The simplicity of operation and reduction in size,
complexity and cost of equipment resulting from eliminating the coding
system used by Steury permits the present invention to provide a
practical, low-cost order collection system for use by small businesses.
The present invention also teaches the optional use of a display only
station proximate the sending telephone. When used, this display only
station provides the sender with the ability to verify: (1) that the
receiving station is ready for the message, and (2) that the data
transmitted from the remote location to the central office is correct.
It is therefore the principal object of the present invention to provide a
simple and inexpensive printing apparatus for use with a pushbutton
telephone system which can be used by relatively untrained operators to
record order information from outlying Touch Tone.TM. telephones at an
unattended central station.
It is a further object of the present invention to provide such an order
logging system that records the time each order is placed with the
pertinent order information.
The foregoing features and objects of the present invention are not to be
considered limiting. The best embodiment of the invention known to the
inventors is detailed below, but the present invention should be
understood to be limited only by the scope of the appended claims and
their equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a drawing showing the components of the order recording system
taught by the preferred embodiment of the present invention;
FIG. 2 is a schematic block diagram showing the relationship of the
functional elements of a printer terminal constructed according to the
preferred embodiment of the present invention;
FIG. 3 is an electric schematic diagram of the power supply of a printer
terminal constructed according to the preferred embodiment of the present
invention;
FIG. 4 is an electrical schematic diagram illustrating a first portion of
the input filter and associated answering control circuitry of the printer
terminal of the present invention;
FIG. 5 is an electrical schematic diagram illustrating the second portion
of the input filter and answering circuit of the printer terminal of the
preferred embodiment of the present invention;
FIG. 6 is an electrical schematic diagram illustrating the tone decoder
circuitry of the printer terminal of the preferred embodiment of the
present invention;
FIG. 7 is an electrical schematic detailing the data storage subassembly of
a printer terminal constructed according to the preferred embodiment of
the present invention;
FIG. 8 is an electrical schematic diagram illustrating a first portion of
the programmer of a printer terminal constructed according to the
preferred embodiment of the present invention;
FIG. 9 is an electrical schematic illustrating a second portion of the
programmer for the printer terminal;
FIG. 10 is an electrical schematic illustrating a first portion of the
clock circuitry of the printer terminal constructed according to the
preferred embodiment of the present invention;
FIG. 11 is an electrical schematic illustrating a second portion of the
clock circuitry of the printer terminal constructed according to the
preferred embodiment of the present invention;
FIG. 12 is an electrical schematic illustrating a first portion of the
printer interface of the printer terminal of the present invention;
FIG. 13 is an electrical schematic detailing a second portion of the
printer interface of a printer terminal constructed according to the
present invention;
FIG. 14 is a block diagram showing the functional elements of a source
terminal constructed according to the preferred embodiment of the present
invention;
FIG. 15 is an electrical schematic illustrating the power supply of a
source terminal constructed according to the present invention;
FIG. 16 is an electrical schematic illustrating the input filter circuitry
of a source terminal constructed according to the present invention;
FIG. 17 is an electrical schematic illustrating the tone decoder portion of
a source terminal constructed according to the preferred embodiment of the
present invention;
FIG. 18 is an electrical schematic of a first portion of the data storage
and display circuitry of the source terminal constructed according to the
present invention;
FIG. 19 is an electrical schematic showing the remainder of the data
storage and display circuitry of a source terminal constructed according
to the preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a pictogram showing the component elements of an order system as
taught by the preferred embodiment of the present invention.
Telephone 101 is connected by cable 103 to source terminal 105. Source
terminal 105 is connected through lines 107 to a switched common carrier
network e.g. indicated metaphorically as telephone poles 109. The central
office switching equipment is not shown in this figure.
At the receiving station, common carrier lines 111 are connected to printer
terminal 113, which is connected by line 115 to a receiving Touch Tone.TM.
telephone 117.
Strictly speaking neither receiving telephone 117 nor source terminal 105
is necessary to provide an automatic hard copy order system. Telephone 101
may be directly connected to the common carrier lines and may, in fact, be
any unmodified touch tone telephone. Printer terminal 113 has the capacity
to stand alone. It need not be hooked to a phone.
To operate the system, the receiver of Touch Tone.TM. phone 101 is lifted
and the number associated with receiving telephone 117 is dialed. Printer
terminal 113 answers the telephone. The person placing the order then
pushes the asterisk key on phone 101. This causes printer terminal 113 to
print the time and date in red. A number would then be entered identifying
the person placing the order. After this number the person placing the
order would push the # on the Touch Tone.TM. pad of telephone 101. This
key causes the printer to advance a line. The person using the system
would then enter numeric data indicating the quantity and number of the
part or other item he was ordering. To terminate the order, the operator
may push the # key twice or merely hang up. After approximately 15 seconds
the common carrier will return a dial tone to printer terminal 113 and the
system will disconnect. Source terminal 105 allows the person placing an
order to visually observe the digits he is transmitting prior to the time
they are printed at printer terminal 113.
It should be apparent that the printer terminal can be used with any Touch
Tone.TM. telephone, whether in the same building or across the country.
This makes the system very flexible because order entry terminals are
commonly available.
FUNCTIONAL DESCRIPTION
FIG. 2 is a functional block diagram illustrating the major elements of
printer terminal 113. Telephone signal 201 is attached to input filter and
answering circuit 203. Input filter 203 outputs data signals via line 205
and control signals via line 207. The data signals from line 205 are input
to tone decoders 209 while the control signal on line 207 is input to
programmer 211. Programmer 211 is connected by line 213 to clock 215; by
line 217 to data storage unit 219; and by line 221 to printer interface
unit 223.
Tone decoder 209 is connected by data line 225 to data storage unit 219.
Clock 215 is connected by line 227 to printer interface unit 223 by line
227. Data storage unit 219 is connected by data line 229 to printer
interface unit 223. Clock unit 215 is also connected by line 231 to
display unit 233. Printer interface 223 is connected by line 235 to
printer 237.
Functionally, input signals from phone line 201 are sorted by input filter
and answering circuit 223. Specifically, input filter and answering
circuit 223 provides a control signal to programmer unit 211. This control
signal is responsive to the status of information on phone line 201. A
unique control signal is generated if the input filter and answering
circuit detects an incoming call and a different control signal is
generated if the answering circuit 203 detects a dial tone on phone line
201. These control signals allow programmer unit 211 to control the
operation of the rest of printer terminal 113.
The input filters in input filter and answering circuit 203 divide the
audio tones that comprise the data signals present on phone line 201 into
high and low frequency groups. As will be explained in more detail later,
these low and high frequency tone groups are fed as input to tone decoder
unit 209, which fully decodes the data signals. The decoded data signals
are inputted to data storage unit 219 and then fed, under the control of
programmer 211 to printer interface unit 223 and thence to printer 237.
The output of clock 215 is displayed by display unit 223. The clock's
output is also fed under the control of programmer 211 to printer
interface unit 223 and printed by printer 237.
Each of the functional blocks described in FIG. 2 is described in more
detail below.
Power Supply--Printer Terminal
FIG. 3 is an electrical schematic illustrating a power supply adequate to
supply the required voltages to operate the embodiment of printer terminal
113 described in connection with FIGS. 4 through 13 below.
Line 301 is connected at one end to a source of 115 Volt 60 Hz electric
power and at its other end to the power side of fuse 303. Line 305 is
connected to fuse 303 and to one side of the primary windings of
transformer 307. The other side of the primary windings of transformer 307
are connected by line 309 to a source of 115 V RMS 60 Hz power. Fuse 303
is a 1-amp fuse and transformer 307 is a 115 V 60 Hz to 30 V center-tap
transformer which may be a signal 241-6-24. The center tap of transformer
307 is grounded through line 311. Positive leg 313 of transformer 307 and
negative leg 315 of transformer 307 are connected to a bridge rectifier
circuit 317. Bridge rectifier 317 comprises four 1N4002 rectifiers.
Positive bridge rectifier output 319 is connected to ground 311 by
smoothing capacitors 321 which are 2000 MFD 16-volt electrolytic
capacitors. Negative side 323 of bridge rectifier circuit 317 is connected
to ground through smoothing capacitor 325, which is a 2000 MFD 16-volt
electrolytic capacitor.
Positive output 319 is also connected to input 327 of voltage regulator 331
and to input 333 of voltage regulator 335. Voltage regulator 331 is
preferably an LM340-12 whose ground connection is connected to ground 311
by line 337 and whose output through line 339 is regulated positive 12 V
with respect to ground 311. Positive line 319 becomes output line 341 and
is unregulated positive 15 V with respect to ground 311.
Voltage regulator 335 is preferably an LM340-6, which is connected to
ground 311 via line 343 and produces a regulated 6 V positive output with
respect to ground 311 through its output line 345.
Negative bridge output 323 is connected by line 347 to the input of voltage
regulator 349. Voltage regulator 349 is preferably an LM320-12, which is
connected to ground 311 via line 351 and produces an output of negative 12
V regulated with respect to ground 311 at its output line 351.
Functionally, 115 V 60 cycle AC power is applied at the primary winding of
transformer 307 through fuse 303. The center tap secondary of transformer
307 is connected to bridge rectifier 317 and produces plus and minus 15 V
of pulsating DC. This pulsating DC is smoothed by filter capacitors 321
and 325 and provides unregulated input power to voltage regulators 331,
335 and 349. These voltage regulators produce regulated plus 12 V, plus 6
V and minus 12 V with respect to ground 311 required by the preferred
embodiment of the present invention. Bridge rectifier 317 directly
produces the unregulated 15 V supply required by the preferred embodiment
of the present invention.
Input Filter and Answer Control Circuitry
FIGS. 4 and 5 must be taken together as they comprise the input filter and
answer control circuitry of the preferred embodiment of the present
invention. To correctly read the electrical schematic displayed in these
two figures, the left edge of FIG. 5 should be matched to the right edge
of FIG. 4.
High side 401 of phone line 111 is attached directly by line 403 to
terminal 405 of bridge rectifier assembly 407. High side 401 is also
connected to upper relay armature 409 of relay 411. Low side 413 of phone
line 111 is connected directly by line 415 to terminal 417 of bridge
rectifier circuit 407 and to lower relay armature 419 of relay 411. Bridge
rectifier assembly 407 comprises four 1N4002 diodes connected in a bridge
circuit. Relay 411 is preferably a Potter & Brumfield R10-E1-Z4-V185.
Upper relay armature 409 and lower relay armature 419 are mechanically
coupled and operate as a double-pole single-throw normally open switch.
Upper relay armature contact point 421 is connected to the coil windings
of inductance 423, which is preferably a Microtran T4415. The other side
of the coil winding of inductor 423 is connected to lower relay armature
contact point 425. Relay armature contact point 421 is also connected to
one side of the primary windings 427 of transformer 429, which is
preferably a Microtran MT35. The other side of primary coil winding 427 is
connected to one side of capacitor 431, which is preferably a 39 MFD 50 V
1% electrolytic capacitor. The other side of electrolytic capacitor 431 is
connected to relay contact point 425. Terminal 433 of bridge assembly 407
is connected via line 435 to one side of capacitor 437, which is a 39 MFD
10% 50 V electrolytic capacitor, and to one side of resistor 439, which is
preferably a 1% 1/4-watt 20,000 ohm resistor. Line 435 is also connected
to terminal 2 of optoisolator 441, which is preferably an MCA230
optoisolator. Terminal 1 of optoisolator 441 is connected through resistor
443, which is preferably a 1% 1/4-watt 2,000 ohm resistor, to the other
side of resistor 439 in capacitor 437. The other side of capacitor 437 is
also connected through resistor 445, which is a 10,000 ohm 1% 1/4-watt
resistor, to terminal 447 of bridge circuit 407.
Terminal 4 of optoisolator 441 is connected through line 449 to ground by
line 449. Terminal 5 of optoisolator 441 is connected directly by line 451
to terminal 9 of integrated circuit 453, which is preferably a 74C04, and
indirectly through resistor 455, which is a 1% metal film 1/4-watt 27,000
ohm resistance to Vcc. Terminal 8 of integrated circuit 453 is wired
directly to terminal 11 and terminal 10 of this integrated circuit is
connected via line 457 to terminal 11 of integrated circuit 459, which is
preferably a 74C74. Terminal 10 of integrated circuit 459 is wired by
connector 461 to terminal 12 of the integrated circuit and is connected to
Vcc. Terminal 9 of integrated circuit 459 is connected via lines 463 to
terminals 1 and 2 of integrated circuit 465, which is a D53632N. Terminal
3 of integrated circuit 465 is connected via line 467 to one side of the
coil windings of relay 411. The other side of relay 411 is connected to
plus 15 V from the power supply shown in FIG. 3. Diode 469 is connected in
parallel across the coil windings of relay 411. Diode 469 is a 1N4002.
Transformer 429 has a first secondary winding 471 and a second secondary
winding 473. One side of primary winding 471 is connected through line 473
and resistance 475, which is a 590 ohm 1% 1/4-watt metal film resistor to
ground and to one side of capacitor 477, which is a 0.1 MFD 10% 50 V
capacitor. The other side of capacitor 477 is connected through resistance
479, which is a 10,000 ohm 1% metal film resistor to terminal 3 of
integrated circuit 481, which is preferably an MC1558 dual operational
amplifier. The other side of secondary 471 is connected to one side of
secondary 473 and to one side of resistance 483, which is preferably a 249
ohm 1/4-watt 1% metal film resistor. The other side of resistor 483 is
connected through a potentiometer 485, which is a 100 ohm potentiometer to
ground. The other side of secondary 473 is connected through resistor 487,
which is preferably a 490 ohm 1% 1/4-watt metal film resistor to ground
and to one side of capacitor 489, which is preferably a 2.2 MFD 10% 50 V
capacitor. The other side of capacitor 489 is connected through resistor
491, which is a 1,000 ohm 1% metal film 1/4-watt resistor to terminal 7 of
integrated circuit 493, which is preferably a MC1558 dual operational
amplifier, and to one side of capacitor 495, which is preferably a 0.047
MFD 5% 50 V capacitor, and resistor 497, which is preferably a 2,000 ohm
1% 1/4-watt metal film resistor. Terminal 5 of integrated circuit 493 is
grounded. Terminal 6 of integrated circuit 493 is connected to the other
side of capacitor 495 and to one side of resistor 499, which is a 10,000
ohm 1% 1/4-watt metal film resistor. The other side of resistor 499 is
connected to terminals 1 and 2 of integrated circuit 493 and to one side
of capacitor 501, which is preferably a 0.1 MFD 5% 50 V capacitor.
Terminal 3 of integrated circuit 493 is connected through capacitor 503,
which is a 0.0475% 50 V capacitor to ground. Terminal 3 of integrated
circuit 493 is also connected through resistor 505, which is a 10,000 ohm
1% 1/4-watt metal film resistor to the other side of capacitor 501 and to
one side of resistor 507, which is a 10,000 ohm 1% 1/4-watt metal film
resistor. The other side of resistor 507 and the other side of resistor
497 are connected together and, through diode network 509, which comprises
two parallel reverse polarity 1N914 diodes, to ground.
Terminal 3 of integrated circuit 481 is connected through resistor diode
network 511, which preferably comprises a 10,000 ohm 1% metal film
resistor in parallel with two reversed polarity 1N914 diodes to terminal 1
of integrated circuit 481.
Terminal 1 of integrated circuit 481 is also connected through resistance
513 to terminal 2 of integrated circuit 515, which is preferably an MC1558
dual operational amplifier. Terminals 3 and 5 of integrated circuit 515
are grounded through lines 517 and 519, respectively. Terminal 1 of
integrated circuit 515 is connected through resistance 521 which is
preferably a 10,000 ohm 1% 1/4-watt metal film resistor.
Capacitor 523, which is a 0.01 MFD 50 V 1% capacitor is connected between
terminals 2 and 1 of integrated circuit 515. Resistor 525, which is a 1.17
megohm 1% 1/4-watt metal film resistor is also connected between terminals
1 and 2 of integrated circuit 515. Terminal 2 of integrated circuit 515 is
connected to one side of resistor 527, which is a 46,800 ohm 1% metal film
1/4-watt resistor. The other side of resistor 527 is connected directly to
terminal 1 of integrated circuit 529, which is preferably an MC1558 dual
operational amplifier, and through capacitor 531, which is a 0.01 1% 50 V
capacitor to terminal 2 of integrated circuit 529. Terminal 3 of
integrated circuit 529 is grounded through line 533.
Terminal 6 of integrated circuit 515 is connected through resistor 535,
which is preferably a 10,000 ohm 1% 1/4-watt metal film resistor, to
terminal 4 of integrated circuit 515. Terminal 4 of integrated circuit 515
is connected through resistor 537, which is a 6,800 ohm 1% 1/4-watt metal
film resistor, to terminal 2 of integrated circuit 529.
Terminal 1 of integrated circuit 515 is also connected directly to one side
of capacitor 539, which is a 0.1 MFD 1% 50 V capacitor. The other side of
capacitor 539 is connected through resistor 541, which is a 1,000 ohm 1%
1/4-watt metal film resistor, to terminal 3 of integrated circuit 543.
Integrated circuit 543 is preferably a 567 tone decoder. Terminal 7 of
integrated circuit 543 is connected to ground. Terminal 6 of integrated
circuit 543 is connected through capacitor 545, which is preferably a 0.1
MFD 10% 50 V capacitor, to ground. Terminal 2 of integrated circuit 543 is
connected through capacitor 547, which is preferably a 2.2 MFD 10% 50 V
electrolytic capacitor, to ground. Terminal 1 of integrated circuit 543 is
connected through capacitor 549, which is preferably a 39 MFD 10% 50 V
electrolytic capacitor, to ground. Terminal 6 of integrated circuit 543 is
also connected to one side of potentiometer 551, which is a 10,000 ohm
potentiometer. The other side of potentiometer 551 is connected through
resistor 553, which is preferably a 10,000 ohm 1% 1/4-watt metal film
resistor to terminal 5 of integrated circuit 543. Terminal 4 of integrated
circuit 543 is connected directly to Vcc and to one side of resistor 555,
which is preferably a 2,000 ohm 1% 1/4-watt metal film resistor, and
resistor 557, which is preferably a 10,000 ohm 1/4-watt 1% metal film
resistor. The other side of resistor 557 is connected to terminal 1 of
integrated circuit 543. The other side of resistor 555 is connected to
terminal 8 of integrated circuit 543. Terminal 8 of integrated circuit 567
is also connected via line 559 to terminal 1 of integrated circuit 561,
which is preferably a 74C08. The output of Or Gate 561 is connected by
line 563 to terminal 13 of integrated circuit 459. Terminal 2 of
integrated circuit 561 is connected by line 565 to terminal 7 of
integrated circuit 821 in FIG. 9, which describes the programmer for the
printer terminal of the present invention.
Terminal 1 of integrated circuit 481 is connected to one side of capacitor
567, which is a 0.018 MFD 1% 50 V capacitor. The other side of capacitor
567 is connected to one side of capacitor 569, which is also a 0.018 MFD
1% 50 V capacitor, and through resistor 571, which is a 7.87 ohm 1%
1/4-watt metal film resistor, to ground. The other side of capacitor 569
is connected through resistor 573, which is a 1,780 ohm 1% 1/4-watt metal
film resistor, to terminal 1 of integrated circuit 575, which is
preferably a MC1558 dual operational amplifier; and through capacitor 577,
which is preferably a 0.018 MFD 50 V 1% capacitor, to terminal 3 of
integrated circuit 575 and through resistor 579, which is preferably a
154,000 ohm 1/4-watt 1% metal film resistor, to ground. Terminal 2 of
integrated circuit 575 is directly strapped by conductor 581 to terminal 1
of integrated circuit 575.
Terminal 1 of integrated circuit 575 is connected through resistor 583,
which is an 8.48 ohm 1% 1/4-watt metal film resistor, to one side of
resistor 585, which is also a 3.48 ohm 1% 1/4-watt metal film resistor,
and to one side of capacitor 587, which is preferably a 0.1 MFD 1% 50 V
capacitor. The other side of capacitor 587 is connected to ground. The
other side of resistor 585 is connected through capacitor 589, which is
preferably a 0.443 MFD 1% 50 V capacitor, to terminal 7 of integrated
circuit 575, and through resistor 591, which is preferably also a 3.48 ohm
1% 1/4-watt metal film resistor, to terminal 5 of integrated circuit 575.
Terminal 5 of integrated circuit 575 is connected through capacitor 593,
which is a 0.005 MFD 1% 50 V capacitor, to ground. Terminal 6 of
integrated circuit 575 is strapped by conductor 595 to terminal 7 of
integrated circuit 575.
Terminal 7 of integrated circuit 575 is connected through resistor 597,
which is preferably a 3.48 ohm 1/4-watt 1% metal film resistor, to one
side of resistor 599, which is also a 3.48 ohm 1% 1/4-watt metal film
resistor, and through capacitor 500, which is preferably a 0.1 MFD 1% 50 V
capacitor, to ground. The other side of resistor 599 is connected through
capacitor 502, which is preferably a 0.443 MFD 1% 50 V capacitor, to
terminal 7 of integrated circuit 504, which is preferably an MC1558 dual
operational amplifier; and through resistor 506, which is preferably a
3.48 ohm 1% 1/4-watt metal film resistor, to terminal 5 of integrated
circuit 504. Terminal 5 of integrated circuit 504 is connected through
capacitor 508, which is preferably 0.005 MFD 1% 50 V capacitor, to ground.
Terminal 6 of integrated circuit 504 is strapped by conductor 510 to
terminal 7 of integrated circuit 504.
Terminal 7 of integrated circuit 504 is connected through capacitor 512,
which is preferably a 0.1 MFD 10% 50 V capacitor, to one side of resistor
514, which is preferably a 5,110 ohm 1% 1/4-watt metal film resistor. The
other side of resistor 514 is connected directly to terminal 6 of
integrated circuit 481 and through diode resistor network 516, which is
preferably a 100,000 ohm 1% 1/4-watt metal film resistor, in parallel with
two opposing polarity 1N914 diodes, to terminal 7 of integrated circuit
481. Terminal 5 of integrated circuit 481 is connected through resistor
518, which is preferably a 100,000 ohm 1% 1/4-watt metal film resistor, to
ground. Terminal 7 of integrated circuit 481 is connected through
capacitor 520, which is preferably a 2.2 MFD 10% 50 V capacitor, to one
side of resistor 522, which is preferably a 1,000 ohm 1% 1/4-watt metal
film resistor. The other side of resistor 522 is connected to low tones
output line 524, which is also low tones input line 524 on FIG. 6.
Terminal 1 of integrated circuit 575 is connected through capacitor 526,
which is preferably a 0.01 MFD 1% 50 V capacitor, to one side of capacitor
528, which is also preferably a 0.01 MFD 1% 50 V capacitor, and through
resistor 530, which is preferably a 6,490 ohm 1% 1/4-watt metal film
resistor, to ground. The other side of capacitor 528 is connected through
resistor 532, which is preferably a 1,470 ohm 1% 1/4-watt resistor, to
terminal 1 of integrated circuit 504; and through capacitor 534, which is
preferably a 0.01 MFD 1% 50 V capacitor, to terminal 3 of integrated
circuit 504. Terminal 3 of integrated circuit 504 is connected through
resistor 536, which is preferably a 127,000 ohm 1% 1/4-watt metal film
resistor, to ground. Terminal 2 of integrated circuit 504 is strapped by
conductor 538 to terminal 1 of integrated circuit 504.
Terminal 1 of integrated circuit 504 is connected through capacitor 540,
which is preferably a 0.01 MFD 1% 50 V capacitor, to one side of capacitor
542, which is also a 0.01 MFD 1% 50 V capacitor, and through resistor 544,
which is preferably a 6,490 ohm 1% 1/4-watt metal film resistor, to
ground. The other side of capacitor 542 is connected through resistor 546,
which is preferably a 1,470 ohm 1% 1/4-watt metal film resistor, to
terminal 1 of integrated circuit 481; and through capacitor 448, which is
a 0.01 MFD 1% 50 V capacitor, to terminal 3 of integrated circuit 481.
Terminal 3 of integrated circuit 481 is also connected through resistor
550, which is preferably a 127,000 ohm 1% 1/4-watt metal film resistor, to
ground. Terminal 2 of integrated circuit 481 is strapped by conductor 552
to terminal 1 of integrated circuit 481. Terminal 1 of integrated circuit
481 is connected through capacitor 554, which is a 0.1 MFD 10% 50 V
capacitor, to one side of resistor 556, which is preferably a 5,110 ohm 1%
1/4-watt metal film resistor. The other side of resistor 556 is connected
directly to terminal 2 of integrated circuit 558, which is preferably an
MC1558 dual operational amplifier, and through resistor diode network 560,
which comprises 100,000 ohm 1% 1/4-watt metal film resistor in parallel
with two reversed polarized 1N914 diodes, to terminal 1 of integrated
circuit 558. Terminal 1 of integrated circuit 558 is connected through
capacitor 562, which is preferably a 2.2 MFD 10% 50 V capacitor, to one
side of resistor 564, which is preferably a 1,000 ohm 1% 1/4-watt metal
film resistor. The other side of resistor 564 is connected to high tones
output line 566, which is the same as high tones input line 566 in FIG. 6.
Input Filter, Ready Oscillator, and Answering Circuit
The following is a functional description of the structure described above.
Telephone Answering Circuit
The answering circuit comprises bridge rectifier 407; the RC filter network
made up of resistor 445, capacitor 437, resistor 439 and resistor 443;
optical isolator 441; flip-flop 459 and relay 411.
Bridge rectifier 407 is AC coupled to phone lines 401 and 413. When 20 Hz
ringing voltage is applied to the phone line, capacitor 437 is charged.
The charge in capacitor 437 turns on the light emitting diode in
optoisolator 441. The phototransistor in optical coupler 441 responds to
the light from the diode grounding resistor 455 and flip-flop 459 to
terminal 11. When the ring voltage stops, the capacitor discharges through
resistor 439 and the optoisolator turns off. Resistor 455 is then isolated
from ground and terminal 11 of flip-flop 459 goes back to Vcc. This
provides a positive transition to flip-flop 459's input. This transition
sets the flip-flop output high. This causes terminal 8, which is the Q
output, to go low and indicates a call has been received. A signal is then
output to the programmer, which is described in detail in FIG. 9. Terminal
9 of flip-flop 459 goes high, to the "1" state, and activates relay 411,
which connects phone lines 401 and 413 through double pole relay armatures
409 and 419 to relay contact points 421 and 425, respectively. Closing
these relay contacts connects the pole line to holding coil 423 and input
windings 427 of transformer 429.
Now that the phone line is connected to the printer terminal, it must be
reset or disconnected in some manner. The present invention can accomplish
this function in two different ways. First, the programmer described in
connection with FIG. 9 below can logically determine that a transmission
has been concluded. If this happens, the programmer transmits a logic "1",
or high data signal, through line 565 to Or Gate integrated circuit 561,
which resets flip-flop 459 by causing line 563 to go high and thus inputs
a logic "1" to terminal 13 of flip-flop 459. The other method of resetting
the present invention is for the answering circuit to detect a dial tone
through hybrid transformer 429. In this second case, the active filter
comprising operational amplifiers 515 and 529 and their associated RC
networks drive tone decoder integrated circuit 543 which decodes the 340
Hz dial tone. If the source station is hung up without a command to reset
the printer terminal, the central station switching equipment of the
telephone company will return a dial tone to the printer terminal after
about 15 seconds. This is a "calling party disconnect". This action
automatically resets the answering circuit by causing integrated circuit
543 to output a logic "1", or high signal, through line 559 to terminal 1
of Or Gate integrated circuit 561, upon the detection of a 340 Hz dial
tone. This logic "1" at terminal 1 of integrated circuit 561 causes line
563 to go high, which inputs a logic "1" at terminal 13 of integrated
circuit flip-flop 459, which resets the flip-flop.
Ready Oscillator
Integrated circuit 493 comprises two operational amplifiers which make up a
200 Hz oscillator. The output of this oscillator is applied to the hybrid
secondary winding 473 of hybrid transformer 429 and thus to the phone
line. When a source terminal is used, as will be described later, this 200
Hz tone tells the source terminal that the printer terminal is ready to
receive data.
Input Filter
The Touch Tone.TM. dialing system developed by the Bell Telephone Company
codes all numeric and symbolic keys with a two-tone system. These
two-tones comprise one tone from a low frequency group and one tone from a
high frequency group. Both tones must be present to define a specific key.
The present invention requires an input filter to remove the 200 Hz ready
tone and to separate the group of high tones from the group of low tones
before these tones can be applied to the tone coder circuitry described in
FIG. 6, below. This removal and separation is accomplished in the present
invention as follows: integrated circuit 481, terminal 7, is a buffer
amplifier that drives the dial tone filter in the input filter circuit.
Integrated circuit 575, terminal 1, is a high pass filter that removes the
200 Hz ready signal. Integrated circuit 575, terminal 7, and 504, terminal
7, and their associated RC networks, are active low pass filters that
remove the tones in the high frequency group so that only the tones in the
low frequency group remain. These low frequency signals are applied to
integrated circuit 458, terminal 7, which acts as a voltage limiter to
control the amptitude of the low frequency tones that are input to the
decoder circuitry described below in connection with FIG. 6. Amplifiers
504, terminal 1, and 575 terminal 1, and their associated RC networks,
form active high pass filters that remove low frequency tones and allow
only the tones from the high frequency group to pass. These high frequency
tones are applied to integrated circuit 458, which acts as a voltage
limiter to drive high frequency input 556 of the tone decoders described
below in connection with FIG. 6.
Tone Decoder
FIG. 6 is an electrical schematic illustrating the tone decoder circuitry
of the printer terminal of the present invention.
The tone decoder comprises seven 567 tone decoders. Tone decoder 601 goes
low when a 697 Hz tone is detected; tone decoder 603 goes low when a 770
Hz tone is detected; tone decoder 605 goes low when a 852 Hz tone is
detected; tone decoder 607 goes low when a 941 Hz tone is detected; tone
decoder 609 goes low when a 1200 Hz tone is detected; tone detector 611
goes low when a 1336 Hz tone is detected; and tone detector 613 goes low
when a 1447 Hz tone is detected.
To "go low" means the logic output signal at pin 8 of the integrated
circuit of the tone detector goes to a logic "0". Low tone input line 524
is connected to terminal 3 of tone decoders 601, 603, 605 and 607. High
tone input line 556 is connected to terminal 3 of tone decoders 607, 611
and 613.
The resistor and capacitor networks associated with each one of tone
decoders 601-613 is identical, therefore only the circuitry associated
with tone decoder 601 will be described in detail.
Vcc is connected directly to terminal 4 of each of the tone decoders.
Terminal 5 of tone decoder 601 is connected through resistor 615, which is
preferably a 6,650 ohm 1% 1/4-watt metal film resistor, to one side of
potentiometer 617, which is a 10,000 ohm potentiometer. The other side of
potentiometer 617 is connected directly to terminal 6 of integrated
circuit 601 and through capacitor 619, which is preferably a 0.1 MFD 10%
50 V capacitor, to ground. Terminal 1 of integrated circuit 601 is
connected through capacitor 621, which is preferably a 2.2 MFD 10% 50 V
capacitor, to ground. Terminal 1 is also connected through resistor 623,
which is preferably a 10,000 ohm 1/4-watt 1% metal film resistor, to Vcc.
Terminal 2 of integrated circuit 601 is connected through capacitor 625,
which is preferably a 1 MFD 10% 50 V capacitor, to ground. Terminal 2 of
integrated circuit 601 is also connected through resistor 627, which is
preferably a 4,700 ohm 1% 1/4-watt metal film resistor, to one side of
capacitor 629, which is preferably a 39 MFD 1% 50 V capacitor. The other
side of capacitor 629 is connected to ground. Terminal 8 of integrated
circuit 601 is connected through resistor 631, which is preferably a 6,800
ohm 1% 1/4-watt metal film resistor, to terminal 4 of integrated circuit
601.
It should be understood that the circuit connections, resistors and
capacitors for each of the tone decoders 601-613 are identical. The set
point frequency of the each individual tone decoders is determined by the
setting of the potentiometer analogous to potentiometer 617 on decoder
601.
Each tone decoder has a unique output line. Integrated circuit 601 has
output line 633 connected to terminal 8. Likewise, integrated circuit 603
has output line 635 connected to its terminal 8; integrated circuit 605
has output line 637 attached to its terminal 8; integrated circuit 607 has
output line 639 attached to its terminal 8; integrated circuit 609 has
output line 641 attached to its terminal 8; integrated circuit 611 has
output line 643 attached to its terminal 8; and integrated circuit 613 has
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