GB2278517A

GB2278517A - Prioritising telephone apparatus

Info

Publication number: GB2278517A
Application number: GB9310872A
Authority: GB
Inventors: Michael Bourton; Antony Shipley; Paul Harris; Terence King; Keith Jacobs
Original assignee: POLITEL Ltd
Current assignee: POLITEL Ltd
Priority date: 1993-05-26
Filing date: 1993-05-26
Publication date: 1994-11-30
Also published as: GB9310872D0

Abstract

Telephony apparatus which operates to allocate to a single telephone exchange line a prioritised one of several inputs. The apparatus includes a relay which operates automatically to interrupt a non-prioritised input if connected to the exchange line to enable the selected prioritised one input to have access to the exchange line.

Description

Improvements in and Relating to Telephony Apparatus This invention relates to telephony apparatus and more especially, but not exclusively, to such apparatus for automatically providing a priority allocation to one of a multiplicity of inputs sharing a single exchange line. The invention also relates to a method of providing a priority allocation to one of a multiplicity of inputs sharing a single exchange line.

Telephonic alarm systems are known in which an auto dialling function of telephone equipment is activated by an alarm responding to an event such as, for example, a fire or a forced entry to a building. Conventionally, such known systems include a dedicated telephone line connected to, for example, a security station remote from the building in which the alarm system is installed. In the event of, for example, a forced entry, the presence of an intruder is recognised by sensors activated by, for example, body heat which operate to activate the auto dialler to alert the connected security station via the dedicated telephone line.

One major disadvantage of such known systems is the need for an expensive dedicated telephone line for transmitting alarm signals in addition to an existing conventional telephone line or lines.

The present invention sets out to provide telephony apparatus which does not suffer from the disadvantage referred to above.

According to the present invention in one aspect, there is provided telephony apparatus which operates to allocate to a single telephone exchange line a prioritised one of several inputs, the apparatus comprising means for automatically interrupting a non-prioritised input if connected to the exchange line to enable the selected prioritised one input to have access to the exchange line.

The means for automatically interrupting a nonprioritised input may comprise a switching relay driven by a timer circuit activated by a prioritised input being received.

In another aspect, the present invention provides a method of allocating to a single telephone exchange line a prioritised one of several inputs, the method including the step of automatically interrupting a non-prioritised input if connected to the exchange line to enable the selected prioritised input to have immediate access to the exchange line.

The invention will now be described by way of example only with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a plan view of a printed circuit board forming part of telephony apparatus in accordance with the invention; and Figure 2 is a circuit diagram of the board illustrated in Figure 1.

The printed circuit board illustrated in Figure 1 is conveniently secured within a casing including entry ports for receiving telephone and power cabling. The board is intended for series connection and includes a mains connected power source 1 generating typically 5 volts, and three sockets 2,3,4 connectedxrespectively to a telephone exchange line, an alarm line including an auto dialling function and one or more conventional telephone lines connected to, for example, hand sets or a facsimile machine. Each socket 2,3,4 conventionally includes four individual connection pins.

Three line switching relays 5,6,7 are provided, relays 5 and 6 operating essentially to transfer incoming or outgoing calls between the conventional lines of socket 4 and the exchange line 2, and relay 7 operating automatically to connect the alarm input of socket 3 to the exchange line 2 notwithstanding the exchange line being otherwise connected when the alarm is activated. Thus, relay 7 operates automatically to recall the exchange line and to present the dialling tone to the unit connected to the alarm line without the need of a knowledge of the target system.

The switching relays 5,6,7 are driven by a timer circuit 8 (typically a "555" timer) which operates in response to the alarm socket 3 being activated in response to a connected sensor detecting, for example, a forced entry to a building.

The printed circuit board includes a plurality of spark erosion diodes 9, which operate to protect the switching relays, resistors 10, transistors 11 and capacitors 12 for appropriately smoothing the power supply.

A potentiometer 14 is provided for setting and fine tuning of the timer 8. Capacitors 15 operate to establish the required time base for the timer 8.

Operation of the circuit board will now be described with reference to Figure 2 in which integers illustrated in Figure 1 have been allocated the same reference numerals.

The circuit, as illustrated, is not powered. When powered and operating as a conventional telephone exchange system (ie the alarm is inactive), relays 5,6 operate conventionally to transfer incoming and outgoing calls between the exchange line socket 2 and normal line socket 4. In the event that the alarm socket 3 is activated by external sensors, electric current passes to power conductive coils 16 to close the switching relay 7 and apply earth to transistor 17 to drive transistor 18 to activate the timer 8. Operation of the timer 8 for a preset time interval (typically 1 or 1.5 seconds) opens the relay 6 thereby interrupting the connection between the line from socket 4 and the exchange socket 2 and enabling the auto dialling function of alarm socket 3 to connect the alarm line to the exchange line.Thus, the exchange line is recalled automatically to present to the unit connected to the alarm line the dialling tone. A knowledge of the circuitry to which the alarm line is connected is not required.

The apparatus therefore operates to provide for the alarm line automatic priority to access the exchange line even if the exchange line is connected to a conventional line.

Thus, when installed, the relays 5,6 operate to connect the single exchange line of socket 2 to the normal telephone lines at socket 4 for, typically, 95% of the time. Occasionally the alarm line at socket 5 is required to be connected to the exchange line whether the exchange line is active or not. When so required, the apparatus operates through relay 7 essentially to force the normal line at socket 4 off the circuit by interrupting the exchange line for a brief interval of time (eg 1 or 1.5 seconds). The apparatus will then return the dial tone to the alarm line to allow the auto dial function to dial and be connected to a preset number via the exchange line. The alarm line will hold the exchange line until it is cleared down by the auto dialling equipment.

It will be understood that whereas the apparatus described above operates to give priority to an alarm line, apparatus in accordance with the invention can also be employed to prioritise other telephonic inputs. For example, the apparatus could operate to give priority to a facsimile input over a conventional telephone line (or vice versa). Alternatively, an input of a modem connected computer could be prioritised over a conventional telephone line (or vice versa). The apparatus operates completely independently of the inputs connected to it, be they telephone inputs, computer inputs, inputs from fax machines, modems or alarms.

Thus, it will be understood that modifications can readily be made to the apparatus described and illustrated without departing from the true scope of the invention.

Claims

1. Telephony apparatus which operates to allocate to a single telephone exchange line a prioritised one of several inputs, the apparatus comprising means for automatically interrupting a non-prioritised input if connected to the exchange line to enable the selected prioritised one input to have access to the exchange line.

2. Apparatus as claimed in Claim 1 wherein the means for automatically interrupting a non-prioritised input comprises a switching relay driven by a timer circuit activated by a prioritised input being received.

3. Apparatus as claimed in Claim 1 or Claim 2 comprising a printed circuit board secured within a casing including entry ports for receiving telephone and power cabling connected to input of the circuit board.

4. Apparatus as claimed in any one of the preceding Claims wherein the prioritised input includes an autodialling function.

5. Apparatus as claimed in Claim 4 wherein the prioritised input is connected to receive signals from an external sensor.

6. Apparatus as claimed in Claim 5 wherein the external sensor forms part of an alarm system.

7. Apparatus as claimed in any of Claims 2 to 6 wherein the switching relay is driven by the timer circuit in response to an alarm socket of the apparatus being activated.

8. A method of allocating to a single telephone exchange line a prioritised one of several inputs, the method including the step of automatically interrupting a non-prioritised input if connected to the exchange line to enable the selected prioritised input to have immediate access to the exchange line.

9. Apparatus for allocating to a single telephone exchange line a prioritised one of several inputs substantially as herein described with reference to Figures 1 and 2 of the accompanying drawings.