Arrangement for requesting service for called telephone subscribers

• US 4,320,258 A
• Filed: 07/07/1980
• Issued: 03/16/1982
• Est. Priority Date: 07/07/1980
• Status: Expired due to Term

• Current Assignee: Bell Telephone Laboratories, Inc. (Nokia Corporation)
• Original Assignee: Bell Telephone Laboratories, Inc. (Nokia Corporation)
• Inventors: McDonald, Henry S.
• Primary Examiner(s): Brown, Thomas W.
• Application Number:
  US06/166,750
• Time in Patent Office: 617 Days
• Field of Search: 179/18 B, 179/5.5, 179/18 BE, 179/18 HB
• US Class Current: 379/201.01
• CPC Class Codes: H04M 19/02 providing ringing current or supervisory tones, e.g. dialling tone or busy tone

Abstract

An improved ringing control circuit in a stored program telephone switching system which provides a called subscriber an interval or window of time after answering a call to send a request for special services such as identification of the number of the calling party. This time interval, initiated when ringing is tripped, delays operation of current sensitive devices which sense current flow in the subscriber line when the party answers the call. This delays completion of the connection by the systems processor which periodically scans the conditions of the current sensitive devices. A detecting device is also provided in the control circuit to detect receipt of the request for service signal during the time interval.

Claims

1. In a switching system which includes common control means for connecting a source of ringing signals to a called subscriber line and for completing a call connection to the subscriber line, a ring control circuit including means responsive to an answer by the subscriber for tripping the ringing source, the tripping means including means for manifesting the subscriber answer, and means operated by the common control means for scanning the answer manifestation to initiate completion of the call connection,

characterized in that

the ring control circuit further includes means for delaying the manifesting of the subscriber answer for an interval of time after the answer by the subscriber without precluding the ringing source tripping to permit the subscriber to signal a request after ringing is tripped and before completion of the call connection and means responsive to the delaying means for detecting receipt of the request signal during the time interval.

2. The arrangement of claim 1, wherein the delaying means includes timing means responsive to the ring tripping for generating the time interval and means responsive to the timing means for rendering the answer manifesting means unresponsive to the subscriber answer until the termination of the time interval.

3. The arrangement of claim 1 or 2, wherein the detecting means includes means for manifesting the request signal receipt to advise the common control scanning means that the subscriber is making a request.

4. The arrangement of claim 3, wherein the delaying means includes means for delaying the manifesting of the request signal receipt until termination of the time interval.

5. A ringing control circuit for a communication system which includes common control means for completing a call connection to a called subscriber line, the ringing control circuit including a source of ringing signals for activating a ringing device of the called subscriber by way of the subscriber line, means responsive to a subscriber answer for interrupting the ringing signals source, a first sensing circuit for selectively sensing flow of current on the subscriber line due to the subscriber answer, means operated by the common control means for scanning conditions of the sensing circuit to initiate completion of the call connection when the subscriber answers, delay means responsive to the interrupting means for delaying the sensing by the sensing circuit for an interval of time without precluding the interrupting of the ringing signal source, and means operated by the delay means for detecting receipt of a request-for-service signal from the subscriber during the time interval.

6. A ringing control circuit, in accordance with claim 5, and further including a second sensing circuit responsive to the detecting means for selectively sensing flow of current on the subscriber line after receipt of the service request signal and means operated by the common control means for scanning conditions of the second sensing circuit.

7. A ringing control circuit, in accordance with claim 6, wherein the delay means further includes means for delaying the sensing by the second sensing circuit for the interval of time.