Note: Descriptions are shown in the official language in which they were submitted.
11-1891
TITLE
TAPE MONITORIN~ AND CONTROL FOR
CENTRALLY LOCATED AUTOMATIC ANSW~:RIN~
AND RECORDING EQUIPMENT
BACKGROUND OF THR INVENTION
(l~ Field of the Invention
The present invention relates to telephone answering
systems and more particularly to systems employing call answering
and recording equipment located remotely from the telephone sub-
scriber's equipment.
~2~ Description of the Prior Art
Equipment has frequently been provided in prior art
telephone systems for automatically answering calls to customer
stations when the called party is not available to do so. Such
lS equipment is usually arranged to answer each call with a recorded
announcement, to record any message from the caller and afterward
to play back the recorded messages to the called customer. A
variety of other features are also usually supplied by this equip-
ment. For example, the customer generally is permitted to record
and check his own answer announcement, and to repeat and skip
certain passages during the playback period.
To provide these and other features present day equip-
ment is usually located on the customer's premises. As a result
installation and maintenance procedures are complicated because
telephone company personnel must visit many locations to install
and service equipment. In addition the customer desiring such
answering service is presented with space problems in locating
the additional equipment adjacent to telephone. Obviously such
conditions increase the cost of service. It has been suggested
that in order to reduce the service cost and simplify installation
and maintenance procedures, that the answering equipment be located
--1 -- .
lO~
at a telephone celltr21 office. While s~lch arrangements overcome
to some extent the foregoing objections, the provision of many
features of answering service which are fre~ucntly requested
required by customers is not possihle. For instance, the customer
is unahle to record his own answering announcement, instead he is
required to use one prepared by the telephone company while he is
given no control over the repeating or skipping of messages during
play~)ack. The service is further restricted when the customer
can only obtain messages or playback at his own station.
Many of these objections have been overcome by a tele-
phone answering system disclosed in IJ.S. Patent No. 3,141,931 to
Alfred Zarouni. However the Zarouni patent teaches that each
customer who desires telephone answering service be assigned two
line appearances in the switching network at the telephone central
office. One of these lines is connected to the customer's answering
equipment and with the line connected to the customer's station, it
is used for ordinary telephone service. The other appearance is
connected to the answering equipment by means of an answer and
record line. This latter line is a so-called "unlisted" line,
that is without a published directory number and is used for
allowing the customer to control his answering equipment.
It is obvious of course from the foregoing that the
requirement for two telephone lines and the attendant disadvantages
thereto are less than desirable. Such disadvantages include cost,
service maintenance, etc. as well as the possibility that if a
person other than the customer subscribing to such service, dis-
covers the unlisted number, he may be able to playback and monitor
messages not intended for him. The system taught by Zarouni
obviously lacks the privacy retaining features of prior art
answering systems which were located on the customer's own pre-
mises.
-2-
lQ'~
Accorclingly it is the princ;plc ol~ject of the present
invention to ovcrcome the disadvnntages of prior art telephone
answering and recording systems and to particularly ~rovide a
telephone ans-~ering and recording system that may be located in a
telephone central office or other centralized location which re-
quires but a single telephone line ~etween the customer's equip-
ment and the ccntralized location for normal operation, and
according]y provides the s~me privacy associatecl with such equip-
ment when it is located at a customer controlled location.
SU~ARY OF THE INVFNTION
The answering and recording equipment of the present
invention provides a customer-user with automatic answering
capability twenty-four hours a dav. The system monitors the
customer's line and after a predetermined number of rings, if
unanswered, answers the telephone with the customer's previously
recorded announcement message. It then switches to record a
message from the caller. The equipment is located in either a
telephone central office or a central location within certain
predetermined limits from a telephone central office. In either
case however certain isolation equipment is located and included
at the telephone central office.
The answering and recording equipment of the present
invention incorporates so-called "cassette" magnetic tape
cartridges. The outgoing or announcement message is recorded
on a cassette type endless loop cartridge while incoming messages
are recorded on a cassette type reel-to-reel cartridge. The
equipment of the present invention includes such features as a
fail-safe circuit to prevent the customer's losing messages while
receiving an incoming call during the playback function. Alarm
circuitry is provided to monitor the equipment for trouble.
In the arrangement taught by the present invention the
customer can dictate an announcement from his own telephone set
This announcement may be either an answer and record announcement
or answer only announcement. Answer only announcements are normally
limited to light duty such as vacation type answer only mcssages,
it being recommended that heavy duty answer only machines be
employed if that is the prime requisite of the customer. In the
present arrangement, the standard announcement may vary in length
from five to twenty-five seconds. By simple modification even
longcr lengths o answer messages may be employed. The present
equipment is arranged to time the caller and shut off after a
preset amount of recording time. This time is adjustable from
30 to 60 seconds depending upon the customer's needs, and is in-
dependent of the length of the recorded announcement.
It is also possible that the present equipment employs
as an option a voice control circuit. This circuit permits the
calling party to record for a maximum recording period of 30
minutes. However if the caller does not speak for a predetermined
period (such as 12 seconds) the equipment will be disconnected.
Another feature included in the present equipment is the
inclusion of an automatic reset feature that places the recording
equipment in a fast forward mode so as to advance the incoming tape
to the end of all the new messages. This reset takes place if
the telephone line is lost or if the customer answers an incoming
call during the playback function. During the automatic answer
and/or recording cycles the customer's telephone line is monitored.
If the telephone set goes off-hook, the equipment will be dis-
connected from the line preventing the recording of two-way con-
versations. Another feature included in the present equipment is
30- calling party control. This feature permits the equipment to go
1~ 4 ~
on-hook as soon as the calling party gocs on-hoo~. For this
reason the central office employed with this arrangement must bç
of the calling party release type through the connector or ter-
minating Junctor. Incoming messages, retrieved messa~es, or
dictation announcements all employ the same telepllone line to
which the telepllone answering and recording equipment of the
present invention is connected. In this way total security is
achieved because a second line is no`t normally used to retrieve
messages. The equipment is normally equipped with a 30-minute
incoming recording tape. I~hen the tape is exhausted the equip-
ment will not accept any more incoming calls.
The system of the present invention is designed to be
employed with standard DTMF (dual tone multi-frequency) telephone
set. If the customer has a rotary dial telephone set a pocket
oscillator providing the necessary tone signals may be employed.
One pushbutton of the oscillator will duplicate the frequency
generated when the # pushbutton of the touch calling unit is
depressed. The second button of the oscillator duplicates the
frequency of the "3" button of the touch calling unit. A third
button on the oscillator duplicates the frequency of the * button.
To access the recording equipment of the present inven-
tion, the customer merely removes the handset from the hookswitch
and listens for dial tone after which he depresses the # button.
To`disconnect from the equipment, he places the handset back on
the hookswitch which automatically places the answering and
recording equipment in the standby condition. When the equip-
ment has been accessed, dial tone disappears and a 1400 Hz tone
is heard in the telephone handset. The equipment is now waiting
for a command. The # pushbutton must be depressed within five
30~ seconds o~ lifting the handset or the equipment will not respond.,
If an incoming c~ll occurs while the equipment is accessed ringback
tone ~ill be heard in the handset. To answer the call the customer
simply goes on-hook and then returns off-hook to receive the call,
otherwise he may ignore the call and proceed.
To dictate an announcemellt the equipment is accessed as
described above. When the 1400 Hz standhy tone is heard, the
customer will dcpress the * button for five seconds. He will
then release the * button, pause momentarily and dictate the
announcement into the handset. If the equipment is equipped with
the standard announcement tape that announcement will then be
restricted to a maximum of 25 seconds. After dictating the
announcement the customer will depress and hold the ~ pushbutton
for approximately five seconds.
When the announcement tape has completed one complete
cycle it will automatically ~o into the check mode. This time
the customer listens for clear message in five seconds of tone at
the end of the message. If for any reason the announc~ment is
unsastisfactory the mode of operation described above may be re-
peated.
If it is desirable for any reason to set the equipment
for operation in the answer-only mode, the procedure followed by
the customer will be like that described above except that after
the message has been dictated the depressing and holding the #
pushbutton for five seconds thereafter is eliminated.
When the equipment is in the automatic answer mode and
the customer receives an incoming telephone message, and either is
not present to answer his telephone or chooses not to answer it, the
equipment of the present invention will count the number of ringing
cycles. If the count reaches the preset number, the equipment will
then answer the call. At this time the equipment will play the
customer's prcviously recorded announccment. If the tone is
present ~fter the announcement has been made, the e~uipment will
then transfer and begin to record the incoming caller's message.
When the equipment starts to record, a timer starts which after
it reaches a preset tlme causes a tone to be clelivered to the
telephone line after which the equipment is disconnected. As
noted previously a message waiting tone is included which indicates
to the customer that messages have been recorded. This tone is
superin~posed over the first five seconds of dial tone and is
detected when the customer goes off-hook. In this manner he
knows if during his absence incoming calls have been recorded.
The circuit providing this feature is reset when the customer
rewinds the tape to listen to the messages.
When the customer is ready to retrieve messages he
accesses the equipment as described above. When the standby tone
is heard he will depress the "3" pushbutton for approximately two
seconds. The equipment indicates in minutes and seconds the
amount of tape that has messages on it. For example, if the
customer hears the pre-recorded message two minutes and twenty
seconds, it indicates there are two minutes and twenty seconds of
messages on the tape. At this time the customer may decide
whether to listen to the messages now or at a more convenient
time. If he chooses to listen at a later time he merely places
thè handset back on the hookswitch. If however he chooses to
listen to the message at this time, he depresses and holds the
number "3" pushbutton which will cause the tape to rewind. When
the tape if fully rewound and the tone in the handset disappears
the "3" pushbutton is released. At this point the messages
recorded pre~iously are now played back. If while reviewing the
recorded messa~es, the subscr~ber desires to backspace or rewind
~V 4 4 ~ ~ ~
the tape, he may do this at any time. This function is performed
by depressing and holding the number "3" pushbutton for the length
of time of the desired hackspacing or re~inding period. When
released the equipment then plays the recorded messages. The
equipment of the present invention reverts to standhy when the
tape reaches the starting point of the initial rewind. If the
customer desires to save the messages that are on the tape, he
merely places the handset on the hook, if however he wishes to
restore the unit for maximum recording time, he depresses and
`10 holds the number "3" pushbutton until the tone disappears after
which he will depress and hold the # pushbutton until the tone is
heard. The unit will thus be placed in the standby mode and at
the beginning of the recording tape after which the customer may
place the handset on the hookswitch.
As noted previously the equipment may optionally be
equipped with a monitor speaker. When the present equipment
after the preset number of rings answers the call, through the
speaker the customer will hear the rings, the announcerent message
being delivered and the caller recording the message. To answer
the call, the subscriber merely turns the monitor s~eaker volume
all the way down and then goes off-hook with the handset. The
present equipment disconnects from the telephone line and conversa-
tion may continue in the normal manner.
The equipment of the present invention is rack mounted
electronic circuitry. As noted previously the line isolation
apparatus must be located in the telephone central office. Al-
ternately the remainder of the equipment which constitutes its
bulk, may be located in the telephone central office or in some
other central location.
30~
-8-
DF.SCRIPTION Ol: T~l~ DRl~WIi~',(`.S
FI~s. 1 and 2 taken in comhination constitute a com- -
posite block and schematic circuit diagram of tclephone answering
recording cquipment in accordance with the present invention.
~IGs. 3 through 17 and 19 through 21 are schematic cir-
cuit diagrams of various portions of the present invention shown in
block form in PIGs. 1 and 2 referred to above.
~IG. 18 shows the manner in which ~I~s. 1 and 2 are to
be arranged.
In FIGs. 1 and 2 single digit numbers are shown within
the blocks which indicate the terminal numbers shown in the associ-
ated detailed circuit drawing figures. In this way the connection
of the detailed circuitry to the circuitry shown in the block
diagram consisting of FIGs. 1 and 2 may be more easily followed.
DESCRIPTION OF THE PRF.FERRED EMBOnI~NT
Referring now to the accompanying drawings an in-
coming call to a subscriber served by the centralized answering
and recording equipment of the present invention will be described.
It should be noted as mentioned previously that the bu3k of the
equipment to be described, may be located in the telephone central
office but alternately may be located in some other central loca-
tion. However it is required that for each subscriber being served
with equipment in accordance with the present invention, certain
equipment for purposes of providing the necessary isolation of
the telephone line during certain modes of operation must be
located at the telephone central office. This equipment which
is categorically referred to as the line isolation equipment ~ -
consists of relays 110, 130, and 140. Also included are capacitors
161, 162, 164, and diode 183.
30-
g
Incoming ringing signals from the telephonc centraloffice servin~ the suhscribcr, are conducted from the subscriber's
connector, at the IDF, over terminals T and R to terminals ~
and - appearing Oll the MD~ where they are connected directly
to the suhscriber's telephonc at his residence or place of
business. This same ringing signal also appears at the automatic
answering and recording equipment located also in the telephone
central office or other convenient nearby location. Appearing on
terminals T and R of the answering and recording equipment the
incoming ringing signal is applied to the ring count connector
700 tFIG. 7) and therein to the input of a bridge rectifier GR710.
The output signal from the recitfier is applied to the input of an
opto-isolator 720 whose output is utilized to drive a filter sec-
tion consisting of resistor 773 and capacitor 762. The output
is also applied to a differential amplifier 730. This amplifier
acts as a comparator comparing the output signal from the opto-
- isolator to a reference potential. If the output from the opto-
isolator exceeds that of the reference an output will be derived
from amplifier 730. It should also be noted that the filter sec-
tion connected to the output of the opto-isolator provides protec-
tion against dial transients. The output of the amplifier 730
feeds a Schmidt trigger circuit 731 which acts to shape the out- I
going pulse for application to the input of a shift register
coùnter 750. The output of the amplifier 730 is also applied to
reset timer 740, which has a timing period of 10 seconds. The
output of this timer is applied to the enable input of the shift
register counter. In response to each incoming ringing burst
the timer is reset so the memory is not cleared. If the call
is abandoned after 10 seconds the timer will clear the shift
register. Assuming the call is not abandoned incoming pulses from
the Schmidt trigger are applied to the cloc~ input of the shift
register and counting begins.
-10-
1~ ~ 4 ~ ~ 1
The shift register 750 has a nuinher of outputs each of
which go true i.n response to a particular count. nepending upon
the desired number of rings before the recording and ans-~ering
equipment operates, the appropriate output ~ill be strapped to
S other circui.try. In the emhodiment shot~n the o~ltput of the shift
register that is strapped, is that associated with the receipt of
a ifth incoming ri.ng. After five rings are received an output
appears and is transmitted to the announcement motor drive cir-
cuit 400 (FIG. 4) and particularly to transistor 411 Operation
of transistor 411 is effective to start the announcement motor 106.
The tape used for announcements in the present equipment incor-
porates at its beginning a foil section l~hich conducts ground
through switch 1420 (~IG. 14). As the tape advances and ground
is removed from switch 1420 transistor 1401 operates relay 1410.
It should be noted at this time that while a metalized portion of
the tape is used and an electrical contact performs removal of
ground, to effect actuation of the transistor, it may also be
possible to use an optical or light reflecting arrangelaent or
some form of pressure sensitive microswitch at this po:int, it
only being required that as the tape advances a signal is for-
warded which ~ill alternately operate and restore relay 1410.
In response to the operation of relay 1410 through its
contacts 1410A tlle telephone line is now connected to Triac 199.
Relay 141~ also connects a capacitive ground at its contacts 1410C
to relay 250 operating it. In response to-operation of relay 250,
Triac 199 becomes conductive connecting the telephone line directly
to the calling party con~ ol relay 150. In this manner the tele-
phone line is bridged and ringing from the telephone central offîce
is stopped by virtue of the completi.on of the loop formed by relay
150. After a short period of time capacitor 262 discharges causing
relay 250 to be restored.
3 S~
Operation of relay 150 connects ground through resistor
174 to relay 140 causing relay 140 to operate at this time. Relay
140 in operating isolates the subscriber's telephone line as far
as DC signals are concerned from the telephone line. Relay 140 at
its associated contacts 140A and 140B connects relay 110 directly
to the subscriber's line to monitor the subscriber's telephone
line for off-hook conditions at the subscriber's telephone
instrument.
The incoming call as noted previously after five rings
10 has now been connected to the centralized answering and recording
equipment. The equipment is now prepared to playback to the
accessing telephone subscriber the announcement message. Audio
signals from the announcement tape are picked up by head 105
coupled through relay contacts 810D and 810C, to the input of
15 the record/playback amplifier 325 wherein signals are amplified
and then applied through to a 15 ohm resistor 176 to the line
transformer 109. The return path for this signal is through
ground. This signal is then coupled to the opposite windings
of transformer T201 which are connected across the coil of relay
20 150 and also across the telephone line. In this manner the
message on the announcement tape, advising the subscriber that
he has accessed an answering device is coupled over the telephone
line to the accessing telephone subscriber.
After the announcement has been completed a tone at the
25 end of the message recorded on the same tape is played to initiate
what is referred to hereinafter as midcycle shift. This tone picked
up by the transformer 109 is coupled to the input of the differ- I
ential ~one amplifier 910 included in tone decoder 900 (FIG. 9).
-12-
The tone decoder circuitry shown in FI~. 9 will now be
described in detail. Incoming signals are cou~led to dual tone,
detector integrated circuits (IC) 920 and 930. In response to
receipt of any of four frequencies, 1209 Hz, 697 Hz, 1477 Hz, and
941 Hz, a digital "lo~" signal appears on the output terminal of
either of the integrated circuits depending upon which signal has
been received. In the case of 1209 Hz it appears on the output
of IC920, in the case of 697 Hz it appears on the output of the
same IC while 1477 Hz appears on the output of IC930, and 941 HZ
'10 also appears on the output of that same IC. These outputs are then
coupled through logic gate circuitry 940 to timer stages-that are a
portion of IC950. The timer puts out an output signal in response
to a combination of 1209 Hz and 941 Hz, in response to the combina-
tion of tones of 1477 Hz and 697 Hz, and in response to receipt of
the combination of 941 Hz and 1477 Hz signals. Hereinafter the
first combination of 1209 Hz, and 941 Hz will be referred to as
the * frequency, the combination of 1477 Hz and S97 Hz will be
referred to as "3", and the 941 Hz and 1477 Hz, will be referred
to as #. These outputs are then applied (through inverter stage
960) from the tone decoder circuitry to the remaining circuitry of
the centralized answering and recording equipment, as required.
Returning again to the discussion of midcycle shift:
signal tone is received initially at the tone decoder 900 previously
described and because it actually consists of a combination of g41
Hz and 1477 Hz tones an output appears on the # output of tone
decoder. This output signal is then applied to the gate of SCR1901
tFIG. 19) causing it to conduct. In response to conduction of
SCR1901 relay 240 operates. It should be noted that the operating
path for SCR1901 was through contacts of relay 150 and also con-
tacts of relay 230. Operation of relay 240 establishes a short
-13-
-
circuit around COllt~CtS 1410A of relay 141n ~ to hold the line for
the incoming message cycle. Operation of relay 240 is also effec-
tive to operate intcgrated circuit 1110 to start timing. IC1110
is a part of the time-out timer 1100 (FI~. 11) and is adjustable
over a range of 30 to 60 seconds by resistor llnl. Relay 240 also
applies ground tllrougll resistor 172 to thc incoming erase head 101
and ground throllgh diode 182 to the switch input of the record play
amplifier 300 causing the amplifier `to switch from the playback
mode to the record mode.
Incoming signals received over the telephone line at
transformer 109 are now coupled from the transformer to the record
input of the record/playback amplifier 300. Signals amplified
therein are taken from the record output and applied through
contacts 810C and contacts 1610B to the incoming record head 104
wherein they are coupled to magnetic recording tape, used as the
recording nedium in the present equipment.
While it has been shown in the present equipr.ent to
use recording tape and conventional pick up and record heads in
the conventional tape recording/playback arrangement, it should
also be understood that other forms of memory might also be uti-
lized and incoming information might be applied thereto in digital
form and likewise recovered in the same manner.
The incoming message is now recorded. Termination of
the incoming message or the announcement message may be made at
any time during the previously mentioned description in the fol-
lowing manner: First the 30 second timer IC1110 operates after
its time period of 30 seconds to operate relay 230. In response
to operation of relay 230 SCR1901 is rendered nonconductive, ~-
releasing relay 240. Relay 240 restores after a short period of
time tapproximately 3 seconds) because of a discharge time of capa-
citor 262. All other previous]y operated relays also release re-
storing the unit to its normal or unoperated condition.
-14-
~ 3 1
A second manner of disconnecting the answering equipment
occurs when the calling party h~ngs up. ~t this time in a tele-
phone central office having calling party release, the loop voltage
goes momentarily to zero and SCRl99 becomes nonconductive causing
relay 150 to release whicll in turn causes rclay 2~0 to rel~ase in
a manner similar to that previously outline(l which in turn will
cause the other relays to also restore. The third manner in which
the equipment may be disconnected occurs when the subscriber having
answering service provided by the machine of the present invention
answers a call while the machine has already seized the telephone
line. At that time when the subscriber goes off-hook he completes
a loop over terminals - and + at the MDF input to relay 110. At
this time relay 110 operates because of the completed loop. The
associated terminals of relay 110 connects at terminal 110A,
battery to relay 130 causing it to operate through diode 183
which connects to ground on the C lead extending from the tele-
phone central office at terminal C to the IDF. Operation of 130
is effective at its associated contacts to open the te~ephone line
from the telephone answering machine causing the conditions to be
interpreted the same as when the calling party disconnects as out-
lined previously.
Message Recovery or Playback By the Telephone Subscriber
When the subscriber having answering service provided by
the present equipment, goes off-hook he receives dial tone via the
leads from the IDF terminals T and R at the telephone central
office and extending out from the + and - terminals at the MDF.
The telephone central office also connects ground to the C lead of
the IDF at this time. Although ground through diode 183 is present
relay 130 is not operated. This ground is also connected at
terminal 2 to the C lead monitor circuitry 600 and particularly to
-15 -
resistor 672 and to the input of an optical isolator 61~. The
return path from the optical isolator is to the coil of relay
140 which is not operated at this time. Neither ~elay 130 or
140 operate, since insufficient current flow is available to
cause them to o~crate because of the presence of resistor 672
which has a resistance of 100,000 ohms. Currcnt flo~ing through
the optical isolator causes an output which is extended to one of
the inputs of comparator amplifier 620. If the voltage appcaring
on the input is of sufficient magnitude compared to the reference
voltage connected to the other input of amplifier 620, an output
appears from comparator amplifier 620 and is applied to one of the
inputs of an associated amplifier 630 serving as an AND gate whose
output is connected to transistor 682. The output from the com-
parator amplifier is also connected to a timer section 640 of the
"C LEAD" monitor 600 whose output provides the other input of the
AND gate.
The output from the timer is combined with the direct
output from the comparator amplifier in the AND gate c~rcuitry to
cause operation of transistor 682. After a predetermi,led period
of time the timer times out and through the previously outlined
circuitry transistor 682 is turned off. The duration of operation
of the transistor is approximately 5 seconds. During the operation
of transistor 682 relay 210 is operated which through its contacts
210A capacitively couples transformer 109 to the telephone line.
If previously recorded messages which have not been re-
trieved are present on the recorded message tape of the answering
unit, SCR1212 of message waiting circuit ]200, will be in the con-
ductive mode this occurs because it was gated on during the in-
coming recording of previous messages. It is gated on by relay 240
and will remain on until the operation of 1620 which will be des-
-16-
cribed hcrcin~fter. SCR1212 will conduct groun~ through relay
contacts 210D ~n~l diode 1211 to relay 230 catlsin~ rclay 230 to
operate at this time. Opcration of relay 230 causcs the tone
oscillator 1700 (FIG. 17) ~hich includes transistor 1710 and
associated components to turn on at this time. This oscillator
produces a tone (approximately 1400 ~z) which appears on the
collector o~ transistor 1710 and then is coupled through resistor
1731, relay contacts 210B to the play input of the record/playback
amplifier 300. Amplified signals at the playback output are then
coupled to the telephone line through transformer 109 in the manner
previously described. At the subscriber's instrument a message
waiting tone (1400 Hz) is heard to indicate the presence of
messages on the tape, (at the centralized answering and recording
equipment).
After five seconds this tone will disappear in the manner
previously described. During this same period of time signals
from the telephone line are also coupled to the tone decoder 900
in a manner previously described in connection with midcycle shift.
The # tone is detected, and SCR1520 will be caused to c:onduct and to-
operate relay 1510, over a path that extends through relay contacts
210C. Operation of relay 1510 at its contacts 1510B places a
short across the leads to relays 130 and 140 which will cause
relay 130 to operate. Operation of relay 130 will inhibit relay
140 from operating at this time, also at associated break contacts
130A and 130B isolation of the central office at the line IDF
from the subscriber or the answering machine will also take place.
The telephone line is now capacitively coupled at the IDF by capac-
itor 161 and 162 for monitoring of incoming ringing signals.
-17-
DC powcr is no~ fed to the subscriber through relay 120
relay contacts 1510A and 1510F to the tc]ephone line. The loop
resistancc of the subscribcr's telephone line will now hold rc-lay
120 operated, which in turn will hold relay 1510 operated at con-
tacts 120A. At this point relay 210 will release as the C lead
monitor circuit 600 is no longer conductive.
The unit has now been seized and the sllbscriber will
hear a standby tone. This tone originates with battery through
contacts 120A, through resistor 272 and diode 286, through resistor
1330 and diode 1330 to transistor 1310 will cause transistor 1310
to conduct at this time. Conduction of transistor 1310 will cause
operation of relay 230. When relay 230 operates the tone oscillator
1700 which includes transistor 1710 turns on and tone at the collec-
tor through resistor 1731 through relay contacts 210B through re-
sistor 196 is applied to the input of the playback amplifier 300.
The output from the playback amplifier is connected to the tele-
phone line in the manner previously described.
On hearing standby tone, the subscriber (assuming that
the subscriber has a touch calling telephone) will push the digit
"3" pushbutton to generate the appropriate signals associated with
this number which will be conducted over the intervening telephone
line and through contacts 1510C and capacitor 161 to a winding on
transformer 109. Return is from the transformer back to the tele-
phone line. The tone signals will be coupled from the opposite
winding of the transformer 109 to the input of the tone decoder
900. Input comes in on terminal 1 of the tone decoder 900 and
the output appears on terminal 5. The output on terminal 5 is
then applied to the gate of SCR1630 to render it conductive. The
output from the tone decoder is also applied to the base of tran-
sistor 1640 to render it conductive to place a short across relay
1610 to inhibit its operation at this time. After release of the
tone, transistor 1640 becomes nonconductive and relay 1610 operates
through the previously established operating path set up through
SCR1630 and through diode 1692, resistor 168~ and through contacts
120A to battery. Operation of relay 810 establishes a path through
relay contacts 1510F. to init;ate operation of the incoming motor
designated 102. Ground from SCR1630 causes transistor 1310 to
become nonconductive thus releasin~ relay 230 and the tone oscil-
lator 1700 at this time.
The tape on which incoming recorded messages have been
recorded, also includes a separate track on which indicia indicate
the amount of tape in time that has been used. These markings
may be in minutes, seconds, or any other appropriate form. Signals
as to the amount of tape that has been used are thus in this manner
picked up and coupled through the head 103 and through the play-
back amplifier 300 through contacts of relay 1610 and relay 1620.
After amplification by the playback amplifier they are connected
to the telephone line through the transformer 109 in the manner
previously described. These signals are then heard by the sub-
scriber and indicate the approximate amount of time which hasbeen devoted to recording on the remotely located recording equip-
ment at the telephone central office.
The subscriber may hang up now which will cause the
machine to disconnect in the manner to be described hereinafter. I -
Or alternately he may retrieve the messages that have been recorded
at this time.
Assuming now that the subscriber desires to retrieve
the previously recorded messages he'll operate the "3" pushbutton
on his touch calling telephone, transmitting the associated com-
30- bination of two tones to the answering and recording equipment
-19-
wherein they will be detected in the manner previously described.
This detection result~ in an output from thc number 5 terminal of
the tone decoder which will cause transistor 1640 to conduct
placing a shunt around associated relay lfilO, causing relay 1610
to restore. Prior to its restoration relay 161 n kept capacitor
1672 charged. IJpon its release capacitor 1672 discharges through
a path via resistor 1689 to the base of transistor 1660 which in
turn will cause relay 1620 to operate. Relay 1620 operates and
loc~s over its associated contacts 1620D and diode 1693 and
resistor 1687 back to ground. The operation of relay 1620
switches the input of the playbac~ amplifier from the position
head 103 to the incoming pick up head 104. At this time relay
1610 is restored and relay 1620 is operated. This oper~tion will
cause the tape to rewind by placing ground through relay contacts
1610C and relay contacts 1620B to the head position motor 108,
causing it to remove the head structure from contact with the
associated tape and engage the rewind idler mechanism. As long as
the tone is maintained by the subscriber the tape will be rewound.
While the tape is moving a switch 1430 known as the tape motion
switch in the announce motor seize circuit 1400 is held in alter-
nate operated and restored positions. Pulses from this switch
are applied to the input of Schmidt trigger circuit IC2111 in tape
counter 2100. The output of the Schmidt trigger provides an
input to integrated circuit IC2120 which is a so called "up-down" I
counter. This unit may utilize any of the many conventional forms ~ -
prevalent in the prior art.
Prior to the operation of relay 1620 the counter 2120
was held in the reset mode by application of ground through con-
tacts 1620C. When relay 1620 removes ground at those contacts,
the counter becomes enabled by removal of the ground. The same
-20-
lV~
ground ~as also available to hold compar~tor IC202n of the begin
tape circuit 2000, in the reset condition. That ground which
caused the heacl position motor 108 to retract the head from contact
with the tape in the rewind mode, is also avail~ble from contacts
1610C to reset the timer section o IC2112 throug}l diode 2171.
The output of the timer section from 2112 is applied to the
"up-down" control of the counter 2120. Nhen the timer is in the
reset condition the counter counts "down" while in the time-out
condition it counts "up". Since the unit is in the rewind mode,
counting is down from zero position.
At the same time switch 1430 is pu]sing the Schmidt
trigger IC2111, it is also applying ground pulses through a pulse
shaping network consisting of diode 1404, resistor 1423, diode 1405,
resistors 1424 and 1425, capacitor 1431, and resistor 1426. Its out-
put is applied to the comparator section of IC2020. The output ofthe comparator section of the IC2020 controls a timer section IC203Q
through diode 2063. As long as pulses from the switch 1430
are present pulses are applied to the input of the comparator
circuit which will maintain the associated timer in the reset
condition. Upon the pulses from the switch stopping, the timer
portion of IC2020 will time-out causing relay 2010 to operate.
Relay contacts 2QlOA will place a short circuit across the T and
R leads of the telephone line removing battery from t~e subscriber's
telephone and causing the tone to stop, for both the machine and
the customer. Because tone is no longer present the tone decoder
will release ~he hold which is present in the form of a signal at
the base of transistor 1640 to cause relay 1610 to reoperate. With
both relays 1610 and 1620 operated a ground will be present for
motor 108 to drive the head assembly back to engage the tape at
this time. lhis action places the machine in the playback mode.
Because tke unit is in the playback mode IC2120 is in a count "up"
mode.
-21-
~U~
Messages recorded on the tape arc thus picked up by pick
up head 104, am~lified by the playback amplifier 300 and applied
over line transformer 109 to the telephone line where they are-
conveyed over the telephone line to the subscriber's instrument
where they are monitored. When the machine goes into the playback
mode pulses from t:he tape applied through switcll 1430 are again
available. They reset the timer 2030 that is a portion of beginning
of tape circuit 2000 to cause relay 2010 to release and open the
short circuit applied across the telephone line.
At any point during the monitor or playback mode the
subscriber may operate the numher "3" button of the touch calling
telephone which will cause the associated machine to go into the
rewind mode.
If the subscriber desires to stop monitoring several
courses of action are available. First he may simply hang up
to cause the unit to go into the fast forward mode which will be
described hereinafter. Alternately the unit may be allowed to go
until the counter returns the unit to standby at which time stand-
by tone through relay 230 will he applied to the telephone line to
indicate that the playback mode is completed. Another alternative
permits the subscriber to push the ~ button on his associated touch
calling telephone unit which will cause the unit to go in the stand-
by mode instantly. For better understanding of the above mentioned
modes of termination of the playback operation, they will be
described in more detail hereinafter.
First assuming the subccriber wishes to terminate play-
back by operating the # button at his touch calling telephone.
Tone is decoded in the manner previously outlined by the tone
decoder circuitry and appears in the number "3" terminal of the
tone decoder as an output signal. This signal is then applied
-22- !
1~ 4'~
through diode 2~3 and resistor 1685, to the basc of transistor 1650,
causing transistor 1650 to conduct, placing a shunt across relay
1620 causing it to restore. Thls in turn causcs relay 1610 to
restore placing tlle unit in the standhy mode. If the subscriber
allows the playback operation to go on to its ultimate end. Tone
is returned indicating the unit is in the standly mode, the counter
will cause tlle unit to return to standby. This occurs when the
counter gets to the zero position at which time the comparator
circuit 2113 recognizes an output from the counter and applies an
output signal through diode 2177 through resistor 1685 to the base
of transistor 1650. When this happens transistor 1650 is operated
placing a shunt across relay 1620 causing it to restore which in
turn will cause relay 1610 to restore in the manner described above.
When the subscriber elects to merely hang up at the subscriber
station, the DC loop to relay 120 is broken and relay 120 will
restore. This in turn causes relay 1510 to restore. When relay
1510 restores relay 130 will restore and if the unit is in the
standby condition all other relays will restore at this time.
If the unit is in the playback mode at this time relay 1620 will
hold relay 1610 and itself operated over a path through its own
contacts 1620E to battery. This places the unit into the fast
forward mode by applying a ground through relay contacts 1610C
and relay contacts 1510E to the fast forward circuitry. This
applies ground to the head position motor 108, causing the heads
to be retracted or removed from contact with the tape. This also
causes relay 220 to operate. Combination of operation of the
relay,220 and movement of motor 108 is effective to place the
associated linkage mechanism in the fast forward mode. It should
be noted that contacts on relay 220 insure that the heads are in
contact with the tape, before the mechanism swi~ched to the fast
-23-
1~ 4 ~
forward mode. This arrangement eliminatcs mcchanical difficulties.
Once the unit has been drawn into the fast for~ard mode relays 1610
and 1620 will restore from the counter circuit as previously des-
cribed. Ground rom the fast forw~rd circuitry also prohibits
the unit ~rom decoding any incoming tones received over the tele-
phone line until the unit has reset.
When an end of tape condition exists which ~ill result
in switch 143n no longer producing output pulses relay 2010 will
operate in a manner previously outlined, to cause relay 120 to also
operate this will cause all operated relays to restore. Once the
equipment has reached the end of tape condition described pre-
viously the equipment will no longer answer any incoming messages
until such time as the subscriber has accessed the equipment and
reset it.
As noted previously when the answering equipment of the
present system has been accessed by a party attempting to contact
the subscriber associated with the equipment, and has been unable
to do so he may leave a recording. As a preliminary to making
that recording he receives from the centralized automa~ic answering
and recording equipment a message. This answering message may be
prerecorded, or alternately, be recorded by the subscriber having
answering and recording service in the following manner:
The subscriber will seize the unit by operating his
touch calling telephone # key to place the unit in the standby mode
in the manner previously outlined. As soon as the unit has gone
into the standby mode the subscriber will push the * button on the
touch calling telephone to cause an output at terminal 6 of the
tone decoder 900. This output signal will be applied through
resistor 842 to turn on SCR821. This signal also goes through
diode 823 to turn on transistor 822. Transistor 822 provides a
-24-
1()~;31
shunt path for relay 81n. When tone is removed by the customer,
relay 810 which has been conditioned will now o~erate over the
holding path througll SCR821 ~hich was turned on previously. The
remaining operating path is through resistor 844 back through
the relay contacts 120A.
When relay 810 operates ground is applied through con-
tacts 810B of relay 810 to the record switch input of the
record/playback amplifier causing it to go into the record mode.
Cround is also applied through resistor 171 to the announcement
erase head 102. High frequency bias signals, and audio signals,
through relay contacts 810C and 810D are applied to the record
head, by the record oscillator mechanism to provide for recording
of a new message. Old messages are erased by a DC voltage which
is applied to the erase head. Operation of relay 810 also applys
a signal to the base of transistor 411 ~FIG. 4) causing it to
operate which will cause the announcement motor 106 to operate.
A ground from relay 810 through contacts 810F, and resistor 431
will charge capacitor 421. As noted previously when the contacting
foil moves forward with the tape, switch 1420 operates causing
transistor 1401 to operate which will cause relay 1410 to operate.
When relay 1410 operates SCR821 will be rendered nonconductive,
however relay 810 will remain operated through contacts 810E
on relay 810 and contacts 1410F on relay 1410. Using the hand
set of the telephone the customer will now record any message he
desires.
After he has completed the message he operates the #
signal to record the # tone which is used for midcycle shift in
the answer/record arrangement or alternately he operates no button.
When no tone is recorded the machine will not go into a midcycle
shift. This arrangement is used in the answer only mode.
-25-
When the contact foil on the tapc which is of the endless
loop type again appears at the sw;tch 1420 transistor 1401 is
rendered nonconductive which will cause relay 1410 to restore.
This in turn ~ill cause relay 810 to restore. Motor 106 however
will continue rullning with the discharge of capacitor 421 through
resistor 431 to the base of transistor 412. In this manner the
relay sensing foil t~ill again move past switch 1420 and cause relay
1410 to operate. The unit is now in the check function mode.
During the check mode the just recorded announcement will be played
back over the telephone line to the subscriber so he may verify
that the announcement has been made correctly. As the machine
drive motor 106 continues to advance the answer tape is moved
forward and audio signals that have been recorded are picked up
by pic~ up head 105, conducted to the input of the play amplifier
300, taken from the outputs thereof and applied to transformer 109
and back over the telephone line to the subscriber. The subscriber
having verified the message has been correctly recorder,?, simply
hangs up and disconnects, wherein the machine will disconnect in
the manner previously described.
If it is desired the subject unit may be equipped with
a voice control circuit ~1800) which is associated with the time-
out timer 1100 which keeps resetting the time-out timer as long
as voice signals are present in the telephone line. The voice
control circuitry of itself is conventional.
If the announcement contactor is for some reason inopera-
tive, pulses are no longer available through diode 1023 (FIG. 10~
to keep the timer IC1020 reset. Transistor 551 will still operate
and apply a signal to transistor 1022 which in turn will operate
an alarm lamp 1021 on the unit and operate relay 1010. Relay 1010
will then extend this alarm condition to the telephone central
-26-
10~
office where it may be utilized in any practical manner. This
alarm unit likewise could he used to monitor other functions of
the unit.
It should be noted that if a subscriher using the machine
is in the process of making an annollncement or reviewing recorded
messages, and an incoming call is received from the telephone
central office, a ringing signal through capacitors 161 and 162
will be heard at the subscriber's instrument and accordingly by
simply hanging up the hand set at the instrument, release will
occur in the manner previously described causing relay 120 to re-
store and consequently allow the call from the telephone central
office to be conducted over the ~DF terminals to the subscriber
line. In this manner emergency calls may be received as well as
permitting the subscriber not to miss any calls during the playback
or recall mode of operation.
While but a single embodiment of the present invention
has been shown, it will be obvious to those skilled in the art that
numerous modifications may be made without departing from the
spirit and scope of the invention. It will be particularly
obvious that only certain standard tone combinations have been
employed for control of the circuitry of the present invention.
In view of this it would be most obvious that additional features
can be included within the tone decoding capability of the present
e~uipment. Such additional featuros may include the provision of
circuitry for turning the equipment "on" or "off" from the sub-
scriber's instrument or remotely, or providing a fast forward
mode of operation for the tape equipment.
