GB2266430A - Call connection priority designator - Google Patents

Abstract

A call connection priority designator device I placed between a telecommunications network line L and a terminal apparatus T designates a chosen terminal A to E as low priority, the terminal may have an answering machine connected thereto. A non-designated terminal F has high priority and may have an extension telephone connected thereto that can take control of an incoming call which is being responded to by the answering machine. The device detects when the designated terminal is off- hook, detects when other terminals are off-hook and controls connection to the designated terminal. The device may be housed in a plug-in unit and can be based on an electro-mechanical switch (C, fig 7) or other components. An indicator may be provided to aid adjustment. The device enables call control to be predictably maintained. <IMAGE>

Description

CALL CONNECTION PRIORITY DESIGNATOR This invention relates to a call connection priority designator for use with terminal apparatus attached to telecommunications systems.

Extension wiring plans permit more than one terminal apparatus to be attached to a single telecommunications service line. With these arrangements clashes of actions can occur when originating or receiving calls. In this specification the term clash refers to the overlapping operation of terminal equipment, brought about as a result of independent machine or human stimulus, and which results in a loss of call control. This invention ensures that control is predictably maintained whenever the potential circumstances for a clash arises.

By employing this invention any chosen telecommunications terminal apparatus is designated a low priority. As a result, unless any non-designated terminal connected to the same extension wiring plan goes off-hook, control of the call is always taken by the first designated terminal to go off-hook, and will be kept by that terminal until it returns on-hook, irrespective of the subsequent actions of any other designated terminal, all of which remain disconnected from the line for the call duration.

Should a non-designated terminal go off-hook whilst a designated terminal is off-hook, control of the call is always transferred to that non-designated terminal, and a designated terminal relinquishing control is automatically disconnected from the line until the non-designated terminal returns on-hook.

Whilst one or more non-designated terminals are off-hook all designated terminals remain disconnected from the line irrespective of their hook status.

As an application example the invention can make it possible for a person reaching an extension telephone to take control of an incoming call which is already being responded to by an answering machine. The benefits the invention brings in this application are: - avoids the need to reach the answering machine to take control of the call - removes the possibility of a tie in a race to answer the call at separate locations - immediately silences an announcement being played on the line by the answering machine - disconnects the answering machine causing it to stop recording the conversation unnecessary - stops the conversation at the extension being overheard from the answering machine's loudspeaker - maintains full audible clarity and speech quality at the extension telephone The invention may be housed in a plug-in unit.It is also suitable for fitting to, or incorporation within, telecommunications terminal apparatus, customer premises wiring and extension plans.

The invention comprises the means to connect the telecommunications service to the designated terminal, the means to detect when the designated terminal is off-hook, the means to detect when other terminals are off-hook, and the means to control the action of the connection means. In addition the invention includes as required a means of adjustment to different telephone exchange line resistances and power feeding conditions, an indicator to aid adjustment, and a means to supply full on-hook line voltage to designated terminal equipments A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows where the invention can be placed in a telecommunications system.

Figure 2 is a block diagram of the functional units involved in the process.

Figure 3 is a state transition diagram showing the effect of external actions.

Figure 4 is a logic diagram showing the decision tree for internal actions.

Figure 5 shows a physical realisation of the invention.

Figure 6 shows the breakout arrangements for connecting a circuit implementation.

Figure 7 is a circuit diagram detailing the arrangement of electronic components.

Figure 8 is a circuit diagram of an indicator to aid setting the circuit adjustment.

Figure 9 is a circuit diagram for supplying full on-hook line voltage to a designated terminal Referring to Figure 1 the invention (I) is placed between the telecommunications network line (L) providing service at the network point of attachment (N) and the terminal apparatus (T)to be designated low priority (A,B,C,D or E). Connection of an non-designated terminal (F) is shown for completeness. The network typically presents a direct exchange or switchboard line for interfacing to the extension plan or customer premises wiring (W). Plug and socket arrangements (P) are commonly used to attach terminal apparatus. The invention may be (D) housed in a plug-in unit, (E) form part of an extension plan or customer premises wiring, (C) integrated with an extension cable, (B) form part of the terminal chord, or (A) be built into the terminal apparatus.

Referring to Figure 2 the invention makes use of the following elements: A switching unit (S) to connect the telecommunications service (C) to the designated terminal (D),a functional unit (B) which detects when the designated terminal is off-hook, a functional unit (A) which detects when other terminals are off-hook, and a logical unit (L) which controls the action of the switch.

Referring to Figure 3 the invention can assume 2 states. In state (1) the switch is open and in state (2) the switch is closed. The transition between states (1) and (2) is caused by the designated terminal going off-hook when all other terminals are on-hook. The transition between states (2) and (1) is caused by the designated terminal going on-hook or any non designated terminal going off-hook.

Referring to Figure 4 the flow of logic to control the switch in the invention can be followed. When all terminals are on-hook the switch is open. If any other terminal is detected to be off hook then the switch remains open. Else if the designated terminal is detected not to be off hook then the switch remains open. Else the switch is closed. If a non-designated terminal is detected to be off hook then the switch is opened. Else if the designated terminal is detected not to be on hook then the switch remains closed. Else the switch is opened.

Referring to Figure 5 a preferred physical realisation of the invention is as connector accessory with plug (B) and socket (A) conforming to national standards.

Referring to Figure 6 the breakout arrangements between plug (B) and socket (A) are for connecting a circuit implementation of the invention at points (X,Y) so that the circuit is in line with the terminal to be designated low priority.

Referring to Figure 7 the circuit diagram shows a practical arrangement of components for a preferred design of the invention based on an electro-mechanical switch. The circuit comprises connection points (X,Y), between which are two series connected sections. Resistor (R) shunting reed relay winding (W) and spanned by points (PQ). Reed relay contacts (C) shunting two zener diodes (Z) and spanned by points (TU). In operation the circuit behaves as follows. When not shorted out of circuit by the reed relay contacts (C), the two zener diodes (Z) serve to detect when all other terminals are on-hook. They will pass current to the reed relay winding (W) independent of line polarity only when the line voltage exceeds their threshold and the designated terminal goes off hook.

This current then suffices to cause the relay contacts to close. The resistor (R) by-passes some current away from the reed relay winding so that there is insufficient to hold the contacts closed when another terminal goes off hook. The voltage appearing across PQ indicates the current flowing to the designated terminal and can be used as an aid to setting the value of the resistor to suit different exchange line resistances and power feeding conditions. A small constant current may be passed via points (T,U) if full on-hook line voltage is required by the designated terminal.

Alternative circuit designs which are obvious developments of this preferred example may be based on the use of semiconductor, opto-electronic, electro-thermal, and electro-magnetic switching components. They may also employ a polarity guard.

Referring to Figure 8 the circuit diagram shows an example of a practical arrangement of components for a resistor adjustment setting aid. A light emitting diode (L) is used to indicate the voltage appearing across PQ. Diodes D form a polarity guard.

Referring to Figure 9 the circuit diagram shows an example of a practical arrangement of components for passing a constant current across points (TU). Component D is a constant current device.

Claims (9)

1 A telecommunications device, for designating a chosen terminal low priority, so that call control is predictably maintained whenever the potential circumstances for its loss arises, and comprising the means to connect the telecommunications service to the designated terminal, the means to detect when the designated terminal is off-hook, the means to detect when other terminals are off-hook, and the means to control the action of the connection means.

2 A call connection priority designator as claimed in claim 1, having a circuit design for a practical implementation based on an electro-mechanical switch.

3 A call connection priority designator as claimed in claim 1, having alternative circuit designs which are obvious developments and which may be based on the use of semiconductor, optoelectronic, electro-thermal, and electro-magnetic switching components.

4 A call connection priority designator as claimed in any preceding claim, having the means of adjustment to different telephone exchange line resistances and power feeding conditions.

5 A call connection priority designator as claimed in any preceding claim , having an indicator to aid adjustment.

6 A call connection priority designator as claimed in any preceding claim, having a means of supplying full on-hook line voltage to designated terminal equipments.

7 A call connection priority designator as claimed in claims 1-6 housed in a plug-in accessory.

8 A call connection priority designator as claimed in claims 1-6 suitable for fitting to or incorporation within terminal apparatus, customer premesis wiring, or extension plans.

9 A call connection priority designator substantially as described herein and with reference to the accompanying Figures 1-9.

9 A call connection priority designator substantially as described herein and with reference to the accompanying Figures 1-9.

Amendments to the claims have been filed as follows 1 A telecommunications device, which is placed between the telecommunications network line providing service and the terminal apparatus to be designated low priority, such that any chosen terminal apparatus is designated low priority where extension wiring plans permit more than one terminal appatatus to be attached to a single telecommunications line by commonly used plug and socket arrangements said device comprising the means to connect the telecommunications service to the designated terminal, the means to detect when the designated terminal is off-hook, the means to detect when other terminals are off-hook, and the means to control the action of the connection means.

2 A call connection priority designator as claimed in claim 1, having a circuit design for a practical implementation based on an electro-mechanical switch.

3 A call connection priority designator as claimed in claim 1, having alternative circuit designs which are obvious developments and which may be based on the use of semiconductor. optoelectronic, electro-thermal, and electro-magnetic switching components.

4 A call connection priority designator as claimed in any preceding claim, having the means of adjustment to different telephone exchange line resistances and power feeding conditions.

5 A call connection priority designator as claimed in any preceding claim , having an indicator to aid adjustment.

6 A call connection priority designator as claimed in any preceding claim, having a means of supplying full on-hook line voltage to designated terminal equipments.

7 A call connection priority designator as claimed in claims 1-6 housed in a plug-in accessory.

8 A call connection priority designator as claimed in claims 1-6 suitable for fitting to or incorporation within terminal apparatus, customer premesis wiring, or extension plans.