Caller ID circuit powered through hookswitch devices
First Claim
1. A communication system, comprising:
- phone line side circuitry capable of being coupled to phone lines;
powered side circuitry capable of being coupled to the phone line side circuitry through an isolation barrier; and
hookswitch circuitry within the phone line side circuitry, the hookswitch circuitry allowing off-hook signals to pass from the phone lines to the phone line side circuitry during off-hook conditions, the hookswitch circuitry drawing current from the phone lines during both on-hook and off-hook conditions.
1 Assignment
0 Petitions
Accused Products
Abstract
The communication system disclosed herein allows for the hookswitch devices to draw loop current from the phone line in both on-hook and off-hook conditions. Thus, even though an on-hook condition occurs, current may be obtained through the hookswitch devices. This feature allows circuitry which operates during on-hook conditions to still receive power from the phone line. Moreover because the hookswitch devices are utilized for drawing power in both on-hook and off-hook conditions, the use of additional switches dedicated to drawing the power during on-hook conditions is not required. For example, loop current may be drawn from the phone line through the hookswitch devices to power circuits used to perform the on-hook caller ID function. The powered circuits may include for example analog to digital converters. The technique disclosed herein for drawing current through the hookswitch devices is particularly useful for communications systems which utilize a capacitive isolation barrier system.
113 Citations
34 Claims
-
1. A communication system, comprising:
-
phone line side circuitry capable of being coupled to phone lines; powered side circuitry capable of being coupled to the phone line side circuitry through an isolation barrier; and hookswitch circuitry within the phone line side circuitry, the hookswitch circuitry allowing off-hook signals to pass from the phone lines to the phone line side circuitry during off-hook conditions, the hookswitch circuitry drawing current from the phone lines during both on-hook and off-hook conditions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A method of providing a communication system capable of being coupled to a phone line, comprising:
-
coupling an isolation barrier between powered side circuitry and phone line side circuitry, the phone line circuitry including hookswitch circuitry; drawing loop current from the phone line through at least one hookswitch switch during off-hook conditions of the communication system; drawing loop current from the phone line through the at least one hookswitch switch during on-hook conditions of the communication system; and powering at least one on-hook circuit by use of the loop current drawn from the phone line during on-hook conditions. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
-
-
21. A hookswitch circuit utilized to attach communication system circuitry to a phone line during off-hook conditions, comprising:
-
a plurality of hookswitch switches, the switches capable of seizing a phone line to pass off-hook data during off-hook conditions and allowing loop current to pass through the hookswitch circuit during off-hook conditions; at least one on-hook circuit within the communication system circuitry, the on-hook circuit functioning at least during on-hook conditions; and at least one power supply line coupling the on-hook circuit to at least one of the hookswitch switches, the at least one hookswitch switch passing current during on-hook conditions so as to create a power supply on the at least one power supply line during on-hook conditions. - View Dependent Claims (22, 23, 24, 25)
-
-
26. A method of operating a hookswitch circuit, comprising:
-
coupling at least one hookswitch switch between a phone line and communication system circuitry; placing the switch in a first on state during off-hook conditions to allow an off-hook current to flow from the phone line through the hookswitch switch to the communication system and to allow off-hook data signals to be passed to the communication system from the phone line; placing the switch in a second on state during at least some on-hook operations to allow on-hook current to flow from the phone line through the hookswitch switch to the communication system; and limiting the amount of on-hook current which flows through the hookswitch switch so that the on-hook current is less than the off-hook current. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34)
-
Specification