Station identification circuit arrangement

• US 4,459,433 A
• Filed: 08/23/1982
• Issued: 07/10/1984
• Est. Priority Date: 12/22/1980
• Status: Expired due to Fees

• Current Assignee: TII Industries, Inc. (Kelta Incorporated)
• Original Assignee: TII Industries, Inc. (Kelta Incorporated)
• Inventors: Wortman, Donald W.
• Primary Examiner(s): Brigance, Gerald L.
• Application Number:
  US06/410,500
• Time in Patent Office: 687 Days
• Field of Search: 179/17 A, 179/17 R, 179/18 FH, 179/81 R
• US Class Current: 379/183
• CPC Class Codes: H04Q 5/24 for two-party-line systems

Abstract

A universal station identification circuit arrangement for use with central office equipment that utilizes either differential or longitudinal detection methods is adapted to be connected to the tip party'"'"'s subscriber drop in a two-party line without requiring access to or rewiring of the tip party'"'"'s telephone. The circuit arrangement may be fabricated in a single unit which may include a ringer isolator together with ANI mark circuits.

Claims

1. A universal station identification circuit arrangement providing first and second ground mark current paths for use with central office equipment utilizing either differential or longitudinal detection methods for identifying a preselected one of two parties on a two-party line in a telephone system when a call is initiated from the preselected party'"'"'s telephone, comprising:

(a) a capacitor;

(b) means for charging said capacitor with loop current flowing in the preselected party'"'"'s subscriber drop when the flow of loop current is initiated by lifting the preselected party'"'"'s telephone off-hook to provide a charge on said capacitor before momentary interruption of said loop current occurs;

(c) current conducting means;

(d) semiconductor means and an active semiconductor connected in series therewith for directing said loop current through said current conducting means after the preselected party'"'"'s telephone is off-hook to initiate a call;

(e) first means under the control of said current conducting means for coupling said first ground mark current path to at least the tip conductor of the line connecting said selected party'"'"'s telephone to said central office whenever said loop current flows;

(f) second means for coupling said second ground mark current path which is normally disconnected from said line; and

(g) means responsive to any momentary interruption of loop current that occurs after the flow of loop current is established by lifting the preselected party'"'"'s telephone off-hook for causing said second means to couple said second mark to the tip conductor of said line when said central office utilizes said longitudinal detection method.

2. A universal station identification circuit arrangement according to claim 1 wherein said active semiconductor is a transistor.

3. A universal station identification circuit arrangement according to claim 1 wherein said second means for providing said second ground mark current path includes means for charging said capacitor comprising first circuit means that normally provides a relatively low impedance current path across said capacitor to discharge and prevent charging of said capacitor when said selected party'"'"'s telephone is on-hook to prevent the flow of loop current in the preselected party'"'"'s subscriber drop, said first circuit means being responsive to the flow of loop current that is initiated by lifting said selected party'"'"'s telephone off-hook to cause said relatively low impedance current path across said capacitor to become a relatively high impedance and second circuit means in series with said capacitor providing a relatively high impedance current path when said selected party telephone is on-hook, said second circuit means being responsive to the flow of said loop current to cause said relatively high impedance current path to become a relatively low impedance, thereby allowing said capacitor to be discharged by said loop current.

4. A universal station identification circuit arrangement according to claim 3 wherein said first circuit means includes a transistor and a biasing circuit arrangement for biasing said first transistor to a relatively low impedance only when said central office battery voltage across the tip and ring conductors of said preselected party'"'"'s subscriber drop is above a preselected threshold that is greater than the D.C. voltage that appears across the tip and ring conductors of said preselected party'"'"'s subscriber drop when loop currents is flowing in the preselected party'"'"'s subscriber drop and said second circuit means includes a transistor and a biasing circuit arrangement for biasing said second transistor to a relatively low impedance only when said loop current is flowing in the preselected party'"'"'s subscriber drop.

5. A universal station identification circuit arrangement according to claim 1 wherein said current conducting means includes relay winding means and wherein said means under the control of said current conducting means includes a set of contacts operated by the flow of current through said winding means to complete a current conducting path between earth ground and at least the tip conductor of the preselected party'"'"'s subscriber drop to establish said first ground mark.

6. A universal station identification circuit arrangement according to claim 5 wherein said winding means is connected in series with a transistor, said transistor and winding means being connected in series with one of the tip or ring conductors or the preselected party'"'"'s subscriber drop and wherein said transistor and winding means are connected in parallel with a second capacitor.

7. A universal station identification circuit arrangement according to claim 6 including means for biasing said transistor to a relatively high impedance when no loop current is flowing in said preselected party'"'"'s subscriber drop and means for establishing a relatively high impedance for said transistor essentially preventing current flow through said winding means whenever the D.C. across the tip and ring conductors of said preselected party'"'"'s subscriber drop is at a value that exists when the preselected party'"'"'s telephone is on-hook, said transistor being biased to a relatively low impedance permitting current to flow therethrough and through said winding means in response to the reduction that takes place in the D.C. voltage across the tip and ring conductors of the preselected party'"'"'s subscribers drop when the preselected party'"'"'s telephone is lifted off-hook to initiate the flow of loop current.

8. A universal station identification circuit arrangement according to claim 1 further including means for indicating when said first means couples said first ground mark current path between earth ground and said tip conductor of the preselected party'"'"'s subscriber drop, said indicating means being serially connected in said first ground mark current path.

9. A universal station identification circuit arrangement according to claim 8 wherein said indicating means includes a diode and a light emitting diode connected in parallel and oppositely poled, said light emitting diode permitting current flow therethrough and emitting light therefrom when current flows in said first or second ground mark current path.

10. A universal station identification circuit arrangement according to claim 1 further including circuit means for momentarily removing said first or second marks during interruptions of said preselected party'"'"'s subscriber drop caused by the dialing by said preselected party.

11. A universal station identification circuit arrangement according to claim 1 further including first circuit means for causing said current conducting means to remove said first ground mark current path when the loop current is reduced below a predetermined value.

12. A universal station identification circuit arrangement according to claim 11 wherein said first circuit means for causing said current conducting means to remove said first ground mark current path is a transistor, said transistor being coupled to said active semiconductor connected in series with said current conducting means and causing said active semiconductor to become a high impedance when said loop current is less than said predetermined value.

13. A universal station identification circuit arrangement according to claim 1 wherein said second means includes circuit means for holding the application of said second mark current path to the tip conductor of said line for a predetermined time interval after the loop is interrupted by dialing.

14. A universal station identification circuit arrangement according to claim 1 further including means for indicating during longitudinal interrogation by said central office when said second means completes a second ground mark current path between earth ground and said tip conductor of the preselected party'"'"'s subscriber drop to establish said second ground mark current path, said indicating means being serially connected in said second ground mark current path and said first ground mark current path.