Method and apparatus for detecting a telephone CPE alerting signal

{
  "publication_number": "US6122353A",
  "country": "US",
  "kind": "A",
  "title": "Method and apparatus for detecting a telephone CPE alerting signal",
  "abstract": "A method and apparatus for verifying that a CAS (Customer Premises Equipment Alerting Signal) detect signal, which indicates the presence of a CAS on a transmission channel, is a valid detect signal, includes structure and process steps for suppressing a signal originating at a local telephone in response to the CAS detect signal. A determination is made whether the CAS detect signal remains in a predetermined condition at a predetermined time after the local telephone signal is suppressed. A validity signal is output when the CAS detect signal remains in the predetermined condition at the predetermined time. False detections are thereby minimized by ignoring detections caused by a signal originating at the local telephone.",
  "claims": [
    "1. An apparatus for detecting, at a user's location adjacent a telephone or integral with the telephone, a valid incoming CAS (Customer Premises Equipment Alerting Signal) on a transmission channel, said apparatus comprising: means for receiving at the user's location an incoming signal including the CAS; means for processing the incoming signal to detect the CAS; means for determining whether the detected CAS is caused by a signal originating at the user's location or by the incoming signal; and means for generating an acknowledge signal when said means for determining determines that the detected CAS is caused by the incoming signal.",
    "2. A method of detecting, at a user's location adjacent a telephone or integral with the telephone, a valid incoming CAS (Customer Premises Equipment Alerting Signal) on a transmission channel, comprising the steps of: receiving at the user's location an incoming signal including the CAS; processing the incoming signal to detect the CAS; determining whether the detected CAS is caused by a signal originating at the user's location or by the incoming signal; and generating an acknowledge signal when said determining step determines that the detected CAS is caused by the incoming signal.",
    "3. An apparatus tor verifying that a CAS (Customer Premises Equipment Alerting Signal) detect signal, which indicates the presence of a CAS on a transmission channel, is a valid detect signal, said apparatus comprising: means for Suppressing a signal originating at a local telephone in response to the CAS detect signal; means for detecting whether the CAS detect signal changes condition in response to suppression of the local telephone signal; and means for outputting a validity signal when said means for detecting detects no change in the condition of the CAS detect signal in response to suppression of the local telephone signal.",
    "4. A method of verifying that a CAS (Customer Premises Equipment Alerting Signal) detect signal, which indicates the presence of a CAS on a transmission channel, is a valid detect signal, said method comprising the steps of: suppressing a signal originating at a local telephone in response to the CAS detect signal; detecting whether the CAS detect signal changes condition in response to suppression of the local telephone signal; and outputting a validity signal when said means for detecting detects no change in the condition of the CAS detect signal in response to suppression of the local telephone signal."
  ],
  "cpc": [
    "H04M 19/041",
    "H04M 1/573",
    "H04M 3/428"
  ],
  "assignees": [
    "CIDCO INC"
  ],
  "filing_date": "1997-07-14",
  "publication_date": "2000-09-19",
  "grant_date": "2000-09-19",
  "priority_date": "1994-12-13",
  "application_number": "US-89210297-A",
  "family_id": "23404581",
  "citations": [
    "US4191862A",
    "US5189634A",
    "US5228080A",
    "US5263084A",
    "US5737400A",
    "US5812649A"
  ]
}