Call diverter function in an early care telephone system

• US 4,689,811 A
• Filed: 04/16/1986
• Issued: 08/25/1987
• Est. Priority Date: 09/17/1984
• Status: Expired due to Fees

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Claeson, Mats I., Lennstrom, Carl A.
• Primary Examiner(s): Dwyer, James L.
• Application Number:
  US06/857,746
• Time in Patent Office: 496 Days
• Field of Search: 379/38, 379/40, 379/46, 379/51, 379/52, 379/211, 379/212, 379/214, 379/210
• US Class Current: 379/38
• CPC Class Codes: H04M 1/006 Call diverting means
• CPC Class Codes: H04M 11/04 with alarm systems, e.g. fire, police or burglar alarm systems

Abstract

A method and apparatus relating to telecommunication systems of the early care telephone type, in which a plurality of subscribers (TA) may be connected to one or more supervision centers (A-C) via a telephone exchange (EX). If any of the centers are night service-connected or out of operation for some reason, a call from a subscriber will be automatically re-routed to another center. When a subscriber equipment unit (SE) associated with a subscriber (TA) has called the telephone number of a duty center (A), the call is answered automatically by an automatic telephone answerer (ATS) or by other equipment which can execute a call diverter function. Instead of a spoken message, there is recorded on the automatic telephone answerer a signal which enables receiving a new telephone number in the subscriber unit (SE), which number is recorded on the telephone answerer. The telephone number message can be accompanied by a single which causes the subscriber unit to disconnect the established telephone connection, or this can be achieved by a caller'"'"'s time monitoring facility'"'"'s disconnecting when criterion acknowledgement signal has not been received. After a suitable time lag, the calling sequence is started once again, but to the supervision center (C) intended by the received telephone number.

Claims

1. A method, which is used in a telecommunication system in which a plurality of subscriber units are connectible via a telephone exchange to common surveillance stations constituting duty centers, said duty centers being selectively operable as night service-connected duty centers and further being selectively operable in conditions in which they are and are ot in operation, said method enabling automatically switching from one of said duty centers to another of said duty centers when calls are made to a night service-connected duty center or to a duty center not in operation, said method comprising activating a subscriber unit to send a predetermined numerical code corresponding to a telephone number to a first of said duty centers according to the number, and adapting said first duty center, if it is night-service-connected or not in operation, to send back to the thusly activated subscriber unit a numerical code previously stored in the first center and corresponding to the telephone number of a second of said duty centers, the latter said number being stored in the subscriber unit, the duty centers when operable sending acknowledgement signals and when night service-connected or not operable omitting to send acknowledgement signals adapting the thusly activated subscriber unit for a predetermined time lapse after omission of an acknowledgement signal from said first duty center to disconnect the connection to said first duty center and for a further time lapse to set up a connection to said second duty center via the telephone exchange by transmitting thereto the stored number of said second duty center, an acknowledgement signal being sent to the subscriber unit from the second duty center on detection of the thusly stored and subsequently transmitted number, an identifying signal being sent from the activated unit subscriber in return to said second duty center.

2. A method as claimed in claim 1, wherein said subscriber equipment detects a code from said first duty center signifying that disconnection of the connection can take place without waiting for the said predetermined time lapse.

3. A telecommunication system comprising a plurality of subscriber units, a telephone exchange, a plurality of surveillance stations constituting duty centers, said exchange selectively connecting the subscriber units to the duty centers, said duty centers being selectively operable as night service-connected duty centers and further being selectively operable in conditions in which they are and are not in operation, and means for automatically switching from one duty center to another duty center when calls are made to a night service-connected duty center or to a duty center not in operation, each subscriber unit (TA1 - TAn) being connectible to respective subscriber-equipment units (SE1 - SEn), each subscriber equipment unit comprising:

first memory means,

means (S) for activating the associated subscriber equipment unit,

control means (MCPU) for storing and reading out and transmission means (SS, IE) for transmitting a predetermined first numerical code corresponding to the telephone number of a first of said duty centers (A) from said first memory means (FNM) to said first duty center (A) via said telephone exchange (EX);

said first duty center (A) comprising

means (NK) for night service-connection of the first duty center, and an automatic anwering means (ATS) for storing and transmitting a second numeral code corresponding to the telephone number of a second of said duty centers (C),

receiving means (SM) for receiving and decoding said second numerical code,

a second memory means (TNM) for temporarily storing said second numerical code while being controlled by said control means (MCPU), after a predetermined time said control means (MCPU) reading said second numerical code from said second memory means (TNM), which is thereby emptied, said transmission means (SS, IE) sending, while under the control of the control means (MCPU), said temporarily stored second numerical code of said second duty center (C) to the exchange (EX), said second duty center including answering equipment (SVU) for receiving ringing signals from the exchange and for transmitting an acknowledgement signal to the associated subscriber equipment unit after having answered a call therefrom, the control means (MCPU) in the subscriber equipment unit including and reading identification information from a third memory means (IDM) and transmitting the same to the answering equipment (SVU) in said second duty center (C) via the transmitter means (SS, IE), identification of the caller taking place in said second duty center.

4. A system as claimed in claim 3, wherein said exchange (EX) is an exchange in a public telephone network.

5. A system as claimed in claim 3, wherein said exchange (EX) is a local exchange.

6. A system as claimed in claim 3, wherein for operational interruption in one said duty center, said answering means (ATS) is connected directly by said exchange (EX) for re-routing calls.

7. A system as claimed in claim 3, wherein said first and third memory means (FNM) and (IDM) are formed from a common memory means.

8. A system as claimed in claim 3, wherein said first and third memory means (FNM) and (IDM) are separate memories.

9. Apparatus as claimed in claim 3, characterized in that said transmitter means (SS, IE) is a transmitter (SS) for DTMF signalling.

10. A system as claimed in claim 3, wherein said transmitter means (SS, IE) includes a transmitter (IE) for interruption impulsing.