GB2107555A - Coded remote control for telephone answering system - Google Patents

Abstract

Access to recorded messages is obtained by sending a multi-bit binary code from a remote location. An eight bit binary code B0 to B7 is selectively set up on the answering machine and correspondingly set up on a hand held portable transmitter. The code is preceded by a twenty two bit preamble and is followed by two trailing bits. The answering machine is processor controlled. <IMAGE>

Description

SPECIFICATION Coded remote control for telephone answering system TECHNICAL FIELD The present invention relates to a control system for a telephone answering system of the type responsive to a remote control units.

BACKGROUND OF THE PRIOR ART U.S. Patent 3,991,272 which was filed in the name of James Darwood describes a telephone answering system which is capable of being operated from a remote point by the transmission of a tone of a predetermined frequency over the telephone line. In response to the tone, the telephone answering system automatically rewinds its message tape back to its origin position, and it then plays back all the accumulated messages recorded on the message tape and transmits the recorded messages over the telephone line to the calling party. Other types of remotely controlled telephone answering systems are also known to the art.

The telephone answering system described in the Darwood patent includes an announcement tape which is activated during an announcement interval (T1) in response to a ring signal received over the telephone line, and a recorded announcement on the announcement tape is transmitted over the telephone line to the calling party during that interval. At the end of the announcement interval (T,), a message tape is activated, and the message from the calling party is recorded on the message tape during an ensuing time interval (T2).

The telephone answering system of the Darwood patent is remotely controlled to enable a person to telephone from any part of the world, and to activate his telephone answering system and cause it to transmit to him over the telephone line all messages accumulated on the message tape. The remote control of the telephone answering unit in the system described in the Darwood patent is achieved by means of a small portable transmitter which is held up by the user to the mouthpiece of the telephone, and which is pushbutton controlled to transmit a tone signal of a predetermined frequency over the telephone line.The telephone answering system responds to the particular tone frequency to activate a control circuit which causes the message tape to be rewound to its origin position, and which then causes the message tape to be set to a playback condition so that the messages recorded on the tape may be successively transmitted over the telephone line to the calling party.

A problem with the remote control system described in the Darwood patent, and with other similar remote control systems, is that anyone with a suitable remote control unit may call the telephone number of a particular telephone answering system, and then control that system and gain access to all messages recorded in the system. This problem is solved by coded remote control systems of the type described, for example, in U.S. Patent 4,196,311 of Hoven, and in other types of remote control systems. In such systems, a number of coding switches are provided in the telephone answering system which are manually set to a predetermined code, and a similar number of coding switches are provided on the remote control unit which are manually set to the same code.Then, when the remote control unit is activated, the tones are transmitted over the telephone line in accordance with a predetermined code, to obtain access to the particular telephone answering unit.

The system of the present invention is of the same general type as described in the Hoven patent, and likewise provides for a number of coding switches in the telephone answering system which are manually set to a predetermined code, and by the provision of a like number of coding switches on the remote control unit which are manually set to the same code. The system of the invention assures that access to a particular telephone answering unit may be achieved only by an authorized person, and only by the initial transmission over the telephone line of tone signals in accordance with a predetermined code. However, the system of the present invention is particularly adapted to microprocessor-controlled telephone answering systems, and it provides a relatively simple and reliable code system for such telephone answering systems.

BRIEF DESCRIPTION OF THE INVENTION The disclosed invention provides a control system for a telephone answering system which includes a first magnetic tape mechanism having a recorded announcement thereon, said announcement being transmitted over the telephone line during a first time interval (T-1) in response to a ring signal received over the telephone line, and a second magnetic tape mechanism for recording messages received over the telephone line during a second time interval (T-2) following the first time interval.The control system includes first circuitry settable to represent a predetermined digital code; audio circuitry adapted to be connected to the telephone line to transmit announcement signals over the telephone line from the first magnetic tape mechanism, to receive message signals from a calling party received over the telephone line to be recorded on the second magnetic tape mechanism, and to receive multi-bit binary coded tone signals from a remote control unit over the telephone line; a microcomputer con nected to the audio circuitry and to said first circuitry to generate an output control signal upon the receipt of tone signals from the audio circuitry matching the setting of the first circuitry; and control circuitry connected to the microcomputer and responsive to the output control signal from the microcomputer for causing the second magnetic tape mechanism to transmit messages recorded thereon successively over the telephone line.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective representation of a telephone answering system which may be remotely controlled, and which incorporates a number of switches which are set to predetermined positions to enable access to the unit only when tone signals are received over the telephone line complying with a predetermined code; Figure 1A is a fragmentary enlarged portion of the telephone answering unit shown in Fig.

1, and showing how the code switches may be set to any selected code; Figure 2 is a perspective view of a remote control unit for operating the telephone answering unit of Fig. 1, and which includes a like number of coding switches; Figure 3 is a schematic diagram of the electronic circuitry included in the remote control unit of Fig. 2; Figures 4a, 4B and 4C are schematic circuit diagrams of the electronic circuitry included in the telephone answering system of Fig. 1; Figure 5 is a schematic diagram of the electronic circuitry associated with the keyboard of the telephone answering unit of Fig.

1; and Figure 6 is a representation of the binary coded tone signals transmitted from the control unit of Fig. 2 over the telephone line to the telephone answering system of Fig. 1; DETAILED DESCRIPTION OF THE ILLUS TRATED EMBODIMENT A typical telephone answering system is shown in Fig. 1, and it includes up/down keys 1 which are used to adjust the volume; a stop key 2 which is used to suspend any function; a REWIND key 3 which is used to rewind the message tape; and a PLAY key 4 which is used to play back received messages.

The system also includes a 2-WAY key 5 which is used to record two-way conversations; and an ANSWER key 5 which is actuated to answer the telephone and take messages.

Also included in the system is a microphone jack 7. A microphone may be plugged into jack 7 to dictate notes on the message tape upon actuation of button 1 5. The unit also includes a series of code switches 8 which, in the illustrated embodiment are eight in num ber. The switches 8 may be set to any predet ermined code, as shown in Fig. 1 A, by operating each individual switch by a pencil, for example, to establish it in either the binary "1" position or in the binary "0" position.

Cassette eject levers 9 are provided to eject either the incoming message cassette 10 or the outgoing announcement cassette 11. A RING SELECT button 1 2 is provided which is used to select the number of rings to be received before the unit will answer. VOX time buttons 1 3 and 1 4 are provided. When button 14 is actuated, a message may be recorded so long as the calling party is speaking, without any time limit. When button 14 is actuated, an incoming message is recorded on the message tape so long as the calling party is speaking, but up to a user programmable limit with a 200 second maximum.

The telephone answering system also includes two announcement buttons 1 6 and 17. When button 16 is operated, the outgoing announcement may be monitored; and when button 1 7 is actuated together with an enable button 20, the outgoing announcement may be recorded. Also included are MESSAGE buttons 18 and 19. When button 1 8 is actuated together with enable button 20, messages are erased. When the button 1 9 is actuated, the message tape is scanned at a faster speed than normal. A digital display is also provided, which will be described.

The telephone answering system of Fig. 1 is operated by a remote control unit 25, shown in Fig. 2. The remote control unit 25 includes a number of coding switches S1 corresponding to the switches 8 on the telephone answering unit of Figs. 1 and 1A, and these switches are set to the same code as the switches of Fig. 1 A, to permit access to the unit. Both the switches 8 and S1 may be set by the point of a pencil, as shown in Fig. 1 A, or by a similar tool.

When the user wishes to receive by telephone messages recorded on the telephone answering system of Fig. 1, he calls his phone number to cause the telephone answering system to come to the line, and at the end of the announcement he then holds the remote control unit 25 up to the mouthpiece of a telephone, and presses a key S2. This causes the remote control unit to transmit the code shown in Fig. 6 over the telephone line to operate the telephone answering system of Fig. 1, and causes it to transmit over the telephone line all the messages that have been accumulated in the unit.

The electronic circuitry of the remote control unit 25 of Fig. 2, as shown in Fig. 3, includes a custom integrated circuit Z1, and associated circuitry, as indicated. The inte grated circuit Z1 is constructed by Silicon Systems Incorporated of Tustin, California and designated by them as Specification No. 1 7C 265H. The custon integrated circuit contains as oscillator, a 32-bit shift register, word counter, frequency dividers and a digital-to analog converter (DAC). The control unit is activated when the user pushes the pushbutton S2, grounding the pin S1. Two sequences of thirty-two 31.25 millisecond tone bursts (bits) are generated, with binary "0" being 683 Hz and with binary "1" being 1024 Hz in a constructed embodiment.The bit pattern is as shown in Fig. 6, namely 000000000000000001110, and an 8-bit code set by the user in the positions of switches S1, and a trailing 01 sequence. The output waveform is a five level staircase approximation to a sine wave which drives speaker SPI directly. After genrating two sequences of the signal shown in Fig. 6, the control unit returns to a quiescent state until reactivated by operating the key S2.

Resistor R1 is a level setting resistor, capacitor C1 provides alternating current bypass control battery B1. X1 is a 32768 Hz quartz crystal, and SPI is a 40 ohm speaker. When the key S2 is depressed, the oscillator frequency divided by 1024 (32 Hz) can be observed at pin 6 (TPI) using a high impedance input (10 meg or greater) oscilloscope.

Pin 7 (TP2) will display a 1-0 pattern representing the 1024 Hz-683 Hz transmitted code.

The entire circuit for the telephone answering system of Fig. 1 is shown in Figs. 4A, 4B, 4C and 5. However, only those portions of the circuit concerned with the coded remote control will be described in detail herein.

The main logic control for the system, as shown in Figs. 4A, 4B and 4C is an RS6500 8-bit microcomputer Z101, which includes four 8-bit parallel bidirectional ports, 2 kilobytes of read-only memory (ROM), 64 bytes of random access memory (RAM), timers, counters, and an oscillator. The microcomputer runs at a speed of 1 MHz. The 2 MHz frequency of crystal Z101 is divided by two internally, and through the use of "pipelining" provides a faster through-put than other microcomputers running at four times the speed.

Port B (PBO-PB7) of the microcomputer Z101 provides all deck control signals, solenoids, motor, prompt signal control, and the enable signal for an audio chip Z102 which is included in the unit. The microcomputer also includes ports C (PCO-PC7) and D (PD0-PD7) which are used for display and keyboard scanning. Port A (PAO-PA7) is used for communication with the audio chip Z102, 60 Hz poling, communication with the prompt tone circuits, and tape motion sensing. In addition to the functions listed above, microcomputer Z101 performs all counting and timing functions, such as RING SELECT and count, ADJ VOX, set and time, VOX time out, remote detection, and remote code verification.

Audio signal processing is done by the audio integrated circuit Z102, which is a custom integrated circuit. Communication between the microcomputer Z101 and the audio integrated circuit Z102 is by way of enable, strobe and data lines. The communication from the microcomputer is in the form of a serial fed 20-bit word. The word contains control data for the amplifiers, signal pass switches, digital volume control, relay control, erase head drive, speaker muting, and frequency response.

The audio integrated circuit Z102 also contains automatic gain control (AGC) and "audio digitizing" circuitry. The audio is digitized and sent to the microcomputer Z101 (PAO) for such functions as VOX, ring detect and remote detect. Bias and beep tone oscillators are also contained in the audio integrated circuit. Current for the erase heads EH 1 and EH2 are provided by the audio integrated circuit Z102 by way of resistors R1 1 2 and R113. The unit includes a microphone MIC-1 which may be plugged in for purposes described above, and it also includes a monitoring speaker SPK-1. The unit includes record and playback heads RPH1 and RPH2 for the announcement and message tapes respectively.The unit also includes erase heads EH-1 and EH-2, mentioned above, for the announcement and message tapes respectively. The message tapes are driven by motor M1. The foregoing components are included on the deck of the unit. The unit plugs into the telephone line by appropriate line plugs 5101 and 5102.

The circuitry associated with the keyboard is shown in Fig. 5. As shown in Fig. 5, display 21 includes a "Bargraph" volume indicator (DS901-DS907); mode indicator light emitting diodes (LED's) (DS908-DS912), and a 3digit seven segment display unit. The display and keyboard are scanned as follows: when "bargraph" information is to be displayed, information is placed on port D (PD0-PD7) of the microcomputer Z101, and port C bit 4 (PC4) is made high (1). Port C bits 0-3 (PC0-PC3) and bit 5 (PC5) are made low (0).

Port C bits 6 and 7 (PC6, PC7) are made high (1). When the remote code switches 8 are to be read port D (PDO-PD7) is made high and port C bit 5 (PC5) is made high (1). Port C bits 6 and 7 (PC6, PC7) are made high (1) then port C bits 0-4 (PCO-PC4) are made low (O). The keyboard and display are scanned at 1 5.625 mS rate. Current sourcing for the LED's is provided by high gain transistors Q901-Q908 and current limiting resistors R901-R908.

The operational description of the integrated circuits included in the system, is as follows.

These, for the most part are state-of-the-art MOS integrated circuits.

Z101 RS6500/1 microcomputer (MOS).

Z101 is an 8-bit microprocessor plus 64 bytes of RAM, 2 K bytes of ROM, four 8-bit bidirectional ports, counters and times.

Z102 M273 custom LS1 audio and driver (MOS).

Z1 02, as mentioned above, is a custom part that contains audio amplifiers, AGC, active filters, digital volume attenuators, 2 oscillators, low impedance power source, and active current sinks.

Z103 LM301 operations amplifier (linear).

Z104 Z105 UPA 2001C high current driver (us).

Z104 and Z105 are high current (300 mA) inverting drivers.

Z106 LM380N-8 audio power amplifier (linear).

Z106 is an audio power amplifier with 34 dB gain, and 1 watt output capability.

Z201 556 timer (linear).

Z201A is configured as an oscillator. The pulse width and frequency are controlled by R204, R206, and C203.

Z201 B is configured as an oscillator. The frequency is controlled by R202, R203, R204, and C202.

Z204 74C76 dual J-k flip-flop (CMOS).

Z204A is configured such that the first negative transition on its clock input (after clear is set high) will cause "Q" to go high (1).

Z204B is configured in a toggle fiip-flop mode. Thus, every negative transition on its clock input (after clear is set high) will cause "Q" to toggle (1 become 0 or 0 becomes 1).

Z205 74C 161 synchronous 4-bit binary counter (CMOS).

After clear is set high (1), each positive transition on its clock input will cause the counter to increment. Thus, the first positive clock pulse will set Q[O] high (1) and the fourth positive clock pulse will set Q[2] high (1).

Z501 4093 quad "nand" Schmitt trigger.

Z502 4029 Presettable binary up/down counter (CMOS).

When a positive pulse is applied to the "P" input, outputs A, B, C, D are reset to logic 0.

If the U/D input is held high (logic 1), the counter will increment at each positive transition of the clock input. If the U/D input is held low (logic 0) the counter will decrement at each positive transition of the clock.

Z503 4068 8-input "nand" gate.

Z504 4069 HEX inverter.

During the outgoing announcement, data is fed to the audio integrated circuit Z102 to ENABLE HEAD, PLAY EQ, V FILT, and LINE RLY (off-hook) and to disable REC OUT, BIAS OUT, RD IN, BEEP OSC, HEAD RLY, MIC IN, SPKR OUT, REC EQ, EH-1 and EH-2. Microcomputer lines PB1 and PB2 are made high (1) providing motor drive and T-l play sole noid operation. Q1 18 is turned off via ZD106 and D116, forcing RD IN of Z102 high (1).

As the announcement tape travels, the audio is digitized by the audio integrated circuit Z102 and fed to the microcomputer Z101 by way of the data line. When the micro-computer senses no activity on the data line for three seconds, the T-1 announcement mode will be terminated, and the T-2 incoming message mode will be initiated.

During the T-2 incoming message mode, data is fed directly to the audio integrated circuit Z102 at the end of the announcement interval T-1 to enable REC EQ, LINE RLY, BIAS OUT, BEEP OSC, REC OUT, SPKR OUT, and EH-2; and to disable EH-1, V FILT, RD IN, HEAD IN, MIC IN, PLAY EQ, AND HEAD ELY. Microcomputer lines PB1 and PB4 are made high (1) enabling M1 and SD3. Digitized audio will be sent to the micromputer Z101 from the audio integrated circuit Z102 on the data line. This data will be examined by the VOX algorithm and T-2 mode will be sustained as long as non-repetitious signals are being received or until maximum time limit has been reached.

Remote detection of signals received from the control unit 25 of Fig. 2 is achieved as follows. The incoming signal (Fig. 6) is digitized by the audio integrated circuit Z102 and sent to the microcomputer Z101 on the data line (PAO). If a valid remote code is received, the microcomputer will send data to the audio integrated circuit to enable PLAY EQ, HEAD IN, LINE RLY and HEAD RLY, and to disable EH-1, EH-2, REC OUT, BIAS OUT, V FILT, RD IN, MIC IN, SPKR OUT, REC EQ, and BEEP OSC.

Microcomputer lines PB1 and PB5 are made high (1) enabling M1 and SD4 causing the T-2 announcement tape to rewind. As the announcement tape is moving, switch S2 on the deck shown in Fig. 4B is opened and closed generating pulses. As long as pulses from S2 are received at the microcomputer (PA5) the unit will remain in rewind. When the message tape T-2 is rewound, microcomputer lines PB1 and PB4 will be made high (1) energizing motor M1 and SD3 (Fig. 4B) thus placing the unit in the remote playback mode. After all messages have been played, the microcomputer will release the T-2 forward solenoid (PB4) and the unit will go to the T-l reset mode.

For the T-1 reset mode, data is fed to the audio integrated circuit Z102 to disable all inputs and outputs. Microcomputer lines PB1 and PB3 are made high (1) enabling M1 and SD2 (T-1 rewind) on the deck. These lines will remain high (1) as long as S1 pulses are received at PB4. The S1 pulses are generated by a switch S1 which opens and closes so long as the announcement tape T-1 is mov ing (see deck of Fig. 4B). When the pulses cease, the telephone answering unit will return to the original answer mode, and is ready to recieve subsequent calls.

The invention provides, therefore, an im proved microcomputer controlled telephone answering system which is equipped with a remote control which transmits remote control signals in accordance with a predetermined code, so that access to the telephone answering unit is achieved only when the particular code is transmitted over the telephone line.

It will be appreciated that while a particular embodiment of the invention has been shown and described, modifications may be made. It is intended in the following claims to cover all modifications which come within the scope of the invention.

Claims (6)

1. A control system which includes a first magnetic tape mechanism having a recorded announcement thereon, said announcement being transmitted over the telephone line during a first time interval (T-1) in response to a ring signal received over the telephone line, and a second magnetic tape mechanism for recording messages received over the telephone line during a second time interval (T-2) following the first time interval; said control system comprising: first circuit means settable to represent a predetermined digital code; audio circuit means adapted to be connected to the telephone line to transmit announcement signals over the telephone line from the first magnetic tape mechanism, to receive message signals from a calling party received over the telephone line to be recorded on the second magnetic tape mechanism, and to receive multi-bit binary coded tone signals from a remote control unit over the telephone line; a microcomputer connected to said audio circuit means and to said first circuit means to generate an output control signal upon the recipt of tone signals from the audio circuitry matching the setting of the first circuit means; and control circuitry connected to the microcomputer and responsive to the output signal from the microcomputer for causing the second magnetic tape mechanism to transmit messages recorded thereon successively over the telephone line.

2. The control system as claimed in Claim 1, in which said first circuit means includes a plurality of manually settable switches.

3. The control system as claimed in Claim 1 or 2, and which includes a control unit for transmitting the multi-bit binary coded tone signals over the telephone line, with a burst of tone signal at a first frequency representing a binary "1" bit, and with a burst of tone signal at a second frequency representing a binary "0" bit.

4. The control system as claimed in Claim 2, in which the control unit transmits the multi-bit binary coded signal with a pre-selected leading multi-bit portion for synchronization and identification purposes, followed by a multi-bit pattern representing the setting of said switches.

5. The control system as claimed in Claim 4, in which the control unit transmits the multi-bit binary coded signal with a trailing multi-bit sequence of a pre-selected pattern for separation purposes.

6. A control system substantially as herein described with reference to and as illustrated in Figs. 2-6 of the accompanying drawings.