Apparatus and method for displaying duration of a call made over a central office line in a keyphone system

• US 5,077,682 A
• Filed: 09/08/1989
• Issued: 12/31/1991
• Est. Priority Date: 12/31/1988
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Seog-Jun
• Primary Examiner(s): Teska, Kevin J.
• Application Number:
  US07/404,561
• Time in Patent Office: 844 Days
• Field of Search: 364/569, 364/705.05, 364/705.06, 364/464.01, 364/464.04, 364/467, 368/4, 368/13, 379/13, 379/34, 379/96, 379/110, 379/116, 379/352, 379/457, 379/130, 379/131, 379/140
• US Class Current: 379/131
• CPC Class Codes: G06Q 30/0284 Time or distance, e.g. usage of parking meters or taximeters
• CPC Class Codes: H04M 15/28 with meter at substation or with calculation of charges at terminal
• CPC Class Codes: H04M 9/005 with subscriber controlled access to an exchange line

Abstract

A method and apparatus for displaying duration of a call that is made over a central office line. The keyphone system having a plurality of keyphone subsets with displaying devices, for carrying out the invention, includes the steps of: notifying call-start by activating a call-duration start timer, if the call over the central office line is started, or, if not, checking whether or not the call is ended; checking whether or not the call-duration display is held, if the call is ended in the above step; checking sequentially whether or not a signal for activating call-duration start timer or call-duration increment timer are activated, if the call is not ended and a time key is not pressed; checking whether or not the central office line is held, if the signal for activating the call-duration start timer or call-duration increment timer is activated, and, if not held, sending call-duration data to a calling keyphone; and clearing a display of the call-duration and displaying a current time, if the time key is pressed and call-duration display is held in the checking step of the signal for activating call-duration start timer or call-duration increment timer.

Claims

1. A method of displaying duration of a call made over a central office line in a keyphone system having a plurality of keyphones with displaying means, the method comprising the steps of:

(a) activating a call-duration start timer for indicating starting of a call upon the call being started, and then checking whether or not the call is ended;

(b) if the call is ended in the step, checking whether or not a call-duration time indicated on said displaying means is at a standstill;

(c) if the call is not ended in said step (a) and a time key is not depressed, checking whether or not a control signal for activating said call-duration start timer or a call-duration timer is applied thereto, said call-duration timer being for counting duration of said call and generating a call-duration time;

(d) checking whether or not the central office line is at a holding state in response to said control signal and, if not at said holding state, sending a value of said call-duration time to said keyphone to display the call-duration time on a said display means; and

(e) if said time key is depressed and said call-duration time indicated on said display means is at a standstill in said step (b), clearing the call-duration time displayed on said display means to display a current time.

2. The method according to claim 1, wherein said step (c) further comprises the steps of:

initializing a call-duration storage buffer to activate said call-duration timer in response to said control signal; and

increasing the call-duration time of said call-duration timer in response to said control signal.

3. A method of displaying duration of a call made over a central office line in a keyphone system having at least one keyphone with a time key and displaying means, the method comprising the steps of:

(a) determining whether or not dialing over said central office line is completed;

(b) recognizing whether or not a call has been started when said dialing is determined to have been completed;

(c) activating a call-duration start timer for indicating starting of said call upon recognizing the call has been started or checking whether or not the call has ended if a call is not recognized as being started;

(d) if it has been determined that the call has been ended in said step, checking whether or not a call-duration time indicated on said displaying means is at a standstill;

(e) if it has been determined that the call is not ended in said step (c), checking whether or not said time key is depressed;

(f) if said time key is determined to not have been depressed in step (e), checking whether or not said call-duration start timer is activated;

(g) if said call-duration start timer is determined not to have been activated in said step (f), checking whether or not a call-duration incrementing timer, for counting duration of said call and generating a call-duration time, is activated;

(h) if said call-duration incrementing timer is determined to have been activated in said step (g), increasing a stored value indicative of a call duration, activating said call-duration incrementing timer after a second has passed and checking whether or not the central office line is in a holding state and, if not in said holding state, sending a value of said call-duration time to said keyphone to display the call-duration time on said display means;

(i) if said time key is determined to have been depressed in step (e), checking if said call-duration time indicated on said display means is at a standstill; and

(j) clearing the call-duration time displayed on said display means to display a current time if said call-duration time indicated on said display means is determined to be at a standstill in said step (i).

4. The method according to claim 3, wherein said step (f) further comprises the steps of:

initializing a call-duration storage buffer to activate said call-duration incrementing timer if said call-duration start timer is determined not to have been activated; and

increasing the call-duration time of said call-duration timer.

5. The method according to claim 3, wherein said step (h) further comprises the steps of:

increasing said call-duration incrementing timer every second;

increase a value stored in a "seconds" storage buffer by one;

initializing said "seconds" storage buffer to a value of zero if said value stored in said "seconds" buffer equals sixty seconds and increasing a value stored in a "minutes" buffer by 1; and

initializing said "minutes" buffer to a value of zero if said value stored in said `minutes` buffer equals one hundred minutes.

6. An apparatus for displaying duration of a call made over a central office line in a keyphone system, having at least one keyphone with a time key and displaying means, comprising:

a random access memory for temporarily storing data;

a read only memory for storing program codes;

a keyphone subscriber circuit for interfacing between said keyphone and a central processing unit;

a call-duration start timer in said central processing unit for indicating starting of a call; and

a call-duration increment timer in said central processing unit for counting duration of said call and generating a call-duration time;

wherein said central processing unit determines whether or not dialing from said keyphone over said central office line is completed,

recognizes whether or not a call has been started when said dialing is determined to have been completed,

activates said call-duration start timer upon recognizing the call has been started or checking whether or not the call has ended if a call is not recognized as being started,

checks whether or not a call-duration time displayed on said displaying means is at a standstill if it has been determined that the call has been ended,

checks whether or not said time key is depressed if it has been determined that the call is not ended,

checks whether or not said call-duration start timer is activated if said time key is determined to not have been depressed,

checks whether or not said call-duration incrementing timer is activated if said call-duration start timer is determined not to have been activated,

increases a value stored in a first buffer indicative of a call duration, if said call-duration incrementing timer is determined to have been activated, activates said call-duration incrementing timer after a second has passed and checks whether or not the central office line is in a holding state, and if not in said holding state, sending a value of said call-duration time to said keyphone via said keyphone subscriber circuit to display the call-duration time of said display means,

checks if said call-duration time indicated on said display means is at a standstill if said time key is determined to have been depressed, and

clears the call-duration time displayed on said display means to display a current time if said call-duration time indicated on said display means is determined to be at a standstill.

7. The apparatus according to claim 6, wherein said central processing unit further initializes a call-duration storage buffer to activate said call-duration incrementing timer if said call-duration start timer is determined not to have been activated, and

increases the call-duration time of said call-duration timer.

8. The apparatus according to claim 7, wherein said central processing unit further increasing said call-duration incrementing timer every second,

increases a value stored in a "seconds" storage buffer by one,

initializes said "seconds" storage buffer to a value of zero if said value stored in said "seconds" buffer equals sixty seconds and increasing a value stored in a "minutes" buffer by 1, and

initializes said "minutes" buffer to a value of zero if said value stored in said `minutes` buffer equals one hundred minutes.