IE42611B1 - Repertory dialler - Google Patents

Abstract

1524028 Automatic exchange systems STANDARD TELEPHONES & CABLES Ltd 14 Oct 1975 [22 Oct 1974] 45604/74 Heading H4K A stored program controlled microprocessor is adapted to function as an impulse repertory dialler. As described under the control of a program in a read only memory ROM and a keyboard, a microprocessor CPU effects reading out the directory number of a selected subscriber from a non- volatile number store EAROM into a random access store RAM used to provide temporary storage during outpulsing. The keyboard has two key banks one used to select repertory subscribers and the other used for digit by digit non-repertory dialling. A monitor speaker may be employed to allow the subscriber to follow the progress of the call until it is transferred to the handset on lifting the latter upon completion of dialling.

Description

This invention relates to repertory dialling arrangements for telephone subsets, and in particular to a repertory dialler having a microprocessor and a non-volatile store to provide 'lexible repertory call-making facilities.

In the past repertory dialling arrangements for telephone ubsets have often been electromechanical in nature and have nvolved such devices as toothed wheels, one for each number • the repertoire, which operate co-operatively with switches d relays. Such arrangements are bulky and can handle only small number of dial codes. Furthermore any change or iition to the call repertoire requires the attention of a illed enginner. Electronic repertory diallers have also been id, but these again generally require the services of an ineer to set up or to change the call repertoire.

The object of the invention is to minimise or to overcome >e disadvantages.

According to the invention there is provided a repertory ler arrangement for a telephone subscriber's instrument, jding a microprocessor adapted to effect the call-making •-ions of the instrument and to control outpulsing to the nge, a first read-only memory adapted to store a program ontrolling the microprocessor, a second random-access y adapted to provide temporary storage for the microprocessor ) outpulsing, a third non-volatile memory adapted to store of predetermined telephone numbers or call-codes, a clock tor for providing timing information to the microprocessor, means including a first array of push-buttons for initiating outpulsing of one of said predetermined telephone numbers or call codes, and means for manual setting up of a call by the subscriber on a digit by digit basis, in which operation of any one of said push-buttons causes the microprocessor to retrieve the corresponding number or call code from the third memory, store the number or call code in the second memory, and effect out-pulsing of said digit of the number or call code sequentially to the exchange.

The telephone subset associated with the repertory dialler may be used in the conventional fashion unaffected by the presence of the repertory dialler.

The repertory dialling arrangement is designed as part of a subscriber's apparatus capable of signalling to the local exchange the identity of a plurality of required telephone numbers or service codes at the instigation of the subscriber by operating a corresponding push-button. A monitor speaker may be employed to allow the subscriber to follow the progress of the call until it is transferred to the handset when outpulsing has been completed and the handset is lifted. The subscriber's apparatus may also be provided with a push-button key block which allows unprogrammed calls to be initiated on a digit by digit basis, and also allows the subscriber to enter new telephone numbers or codes into the repertoire. In a preferred embodiment the digits thus dialled are temporarily stored and the complete number may be repeated by the subscriber by operation of a single push-button. 611 An embodiment of the invention will now be described with reference to the accompanying drawings in which:Figure 1 is a block schematic of the control unit of the repertory dialler arrangement; and Figures 2a to 2,h together are a flow sheet of the operation of the dialler of Figure 1.

The repertory dialler advantageously includes a first push-button key-block for dialling unprogrammed calls and a second key-block for selecting predetermined stored call codes by the operation of any one push button. Further switches may be included to control such facilities as repeat number and call cancel etc.

The repertory dialler arrangement includes a central logic control circuit for operating the various repertory functions of the associated subscriber instrument and for storing the predetermined call codes. The control unit also operates display devices to indicate to the subscriber the status of the dialler and the progress of a dialled call. The various peripheral devices associated with the controller as shown in rigure 1 are all well known in the art and do not require lescription.

A block schematic diagram of the control unit is shown in 'igure 1. A microprocessor CPU controls all the other parts if the control circuit, and through them the whole callmaker. t communicates with the other components of the controller via ata bus bars or highways carrying two types of information, ddresses and data.

The microprocessor and its associated read only memory ROM may be regarded as the functional equivalent of a custom integrated logic circuit. The microprocessor performs arithmetic and Boolean function on data supplied either by itself or by associated memory or input/output devices under the control of a program stored in the read only memory. It also reads from and supplies data to inppt/output devices to control the peripheral circuits.

The active memory associated with the microprocessor is divided into two parts, the most important being a non-volatile number store which is provided by an array of electrically alterable memories. Non-volatility of the memories is obtained by using MNOS technology. High write voltages are used to inject charge into the gate structures of individual MOSFET devices and these charges are stored in the gate structure until altered by further write voltages. The effect of these charges is to alter the gate threshold voltages of the individual MOSFET devices causing particular memory calls to store ONE's or ZERO'S.

The operation of the microprocessor is controlled by a program stored in the read only memory ROM, the position in the program being controlled by a program counter in the microprocessor. Timing of the microprocessor is controlled by a master clock which also provides timing information to the rest of the controller and callmaker.

The controller includes a small random access memory RAM which provides temporary working space for the microprocessor during outpulsing and during writing data into the non-volatile store. The random access memory is also used as the repeat number store.

The repertory of telephone numbers available to the callmaker is stored in a non-volatile store, the electrically alterable memory. This store may be constructed from microcircuits fabricated by a standard metal-nitride-oxide silicon semiconductor process. The memory element in each cell of the memory has a very thin oxide gate. When data is stored in the memory cell an overvoltage is applied to this gate thus permanently implanting an electric charge. This has the effect of changing the gate threshold voltage of the memory cell and is sensed by the output circuits as a ONE or a ZERO.

The keyboard and control inputs and outputs are connected to the data bus via input/output devices which are controlled by the processor and clock. Further monitor signals are input directly to the processor.

The operation of the repertory dialler is described in the flow-sheets of Figures 2a^ to 2^.

OPERATION 1, Start up When power is first applied to the system the microprocessor sets itself to an initial state. The processor then proceeds to a program that sets all controls and relays to ensure that the system enters an idle state. The system is then ready to process any control inputs. 2. Data Input Data is subdivided into three groups, viz address inputs, digit inputs and control inputs. On receipt of an input the microprocessor sorts it into one of two groups, data and address, or control. The inputs are checked for noise or 'bounce' and, if accepted as satisfactory, the microprocessor takes appropriate action, either by out-pulsing, digit storing or controlling peripherals.

If an address or digit input is received the microprocessor decodes this into the appropriate form. If the callmaker is in the store mode the appropriate part of the nonvolatile store is accessed and subsequent digits are written into the non-volatile store. Provision may be made in the program for the internal stacking of addresses and numbers in the RAM where it is possible to enter addresses and numbers faster than they can be transferred to the non-volatile store.

If the callmaker is not in the store mode receipt of a digit or address input causes seizure of the telephone line and, depending on whether an address or digit has been received, to outpulse either the number entered from the key-block on a digit-by-digit basis or the number stored in the non-volatile memory corresponding to the address button received. If digits are entered, the digits are also stored in the random access memory RAM and may be repeated by operation of a repeat button. The program controls the monitor amplifier, dial tone detector and the other peripherals necessary for handling all classes of calls. soil Further facilities may be included such as (a) a means of altering the timing of the output device to cater for different requirements of various telephone systems (b) a means of indicating to the caller that a control has been depressed at a time when it was not valid (c) a means of doubling the number of telephone numbers stored by increasing the non-volatile memory and associating a switch with the address buttons. (d) a means of providing 'timing out' (disconnection) of the device to avoid holding of the exchange equipment (e) a means of providing a monitor facility to allow incoming speech to be received from a loudspeaker and not subject to time-outs as in (d) (f) a means of providing automatic dial tone detection with manual override facility.

Claims (6)

CLAIMS 43611

1. A repertory dialler arrangement for a telephone subscribers instrument, including a microprocessor adapted to effect the call making functions of the instrument and to control outpulsing to the exchange, a first read-only memory adapted to store a program for controlling the microprocessor, a second random-access memory adapted to provide temporary storage for the microprocessor during outpulsing, a third non-volatile memory adapted to store a set of predetermined telephone numbers or call codes, a clock generator for providing timing information to the microprocessor, means including a first array of push-buttons for initiating outpulsing of one of said predetermined telephone numbers or call codes, and means for manual setting up of a call by the subscriber on a digit by digit basis, in which operation of any one of said push-buttons causes the microprocessor to retrieve the corresponding number or call code from the third memory, store the number or call code in the second memory and effect outpulsing of each digit of the number or call code sequentially to the exchange.

2. A repertory dialler arrangement as claimed in claim 1, and in which said third memory is an electrically alterable readonly semiconductor memory having a metal-nitride-oxide-si1 icon construction.

3. A repertory dialler arrangement as claimed in claim 1 or 2, and which includes means for repeat outpulsing of a call code set up manually on a digit by digit basis by the subscriber.

4. A repertory dialler as claimed in claims 1, 2 or 3, and which includes means for indicating to the subscriber the progress of a dialled call during the call setting up process. 3611

5. A repertory dialler arrangement substantially as described herein with reference to Figures 1 and 2 of the accompanying drawings.

6. A telephone subscriber's instrument when fitted with a repertory dialler arrangement as claimed in any one of the preceding claims.