"key off" meaning in English

{
  "forms": [
    {
      "form": "keys off",
      "tags": [
        "present",
        "singular",
        "third-person"
      ]
    },
    {
      "form": "keying off",
      "tags": [
        "participle",
        "present"
      ]
    },
    {
      "form": "keyed off",
      "tags": [
        "participle",
        "past"
      ]
    },
    {
      "form": "keyed off",
      "tags": [
        "past"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "*"
      },
      "expansion": "key off (third-person singular simple present keys off, present participle keying off, simple past and past participle keyed off)",
      "name": "en-verb"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Computing",
          "orig": "en:Computing",
          "parents": [
            "Technology",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        },
        {
          "_dis": "87 13",
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        },
        {
          "_dis": "72 28",
          "kind": "other",
          "name": "English phrasal verbs with particle (off)",
          "parents": [],
          "source": "w+disamb"
        }
      ],
      "examples": [
        {
          "text": "This logic keys off the user's social security number.",
          "type": "example"
        }
      ],
      "glosses": [
        "To take something as a controlling input datum."
      ],
      "id": "en-key_off-en-verb-QMI59c1Y",
      "links": [
        [
          "computing",
          "computing#Noun"
        ]
      ],
      "raw_glosses": [
        "(computing) To take something as a controlling input datum."
      ],
      "topics": [
        "computing",
        "engineering",
        "mathematics",
        "natural-sciences",
        "physical-sciences",
        "sciences"
      ]
    },
    {
      "categories": [],
      "examples": [
        {
          "text": "She keyed off the ignition and went into the house.",
          "type": "example"
        }
      ],
      "glosses": [
        "To turn off something (e.g. a car) using a key."
      ],
      "id": "en-key_off-en-verb-sOm3UQ79",
      "links": [
        [
          "turn off",
          "turn off"
        ]
      ]
    }
  ],
  "word": "key off"
}

{
  "categories": [
    "English entries with incorrect language header",
    "English lemmas",
    "English multiword terms",
    "English phrasal verbs",
    "English phrasal verbs with particle (off)",
    "English verbs"
  ],
  "forms": [
    {
      "form": "keys off",
      "tags": [
        "present",
        "singular",
        "third-person"
      ]
    },
    {
      "form": "keying off",
      "tags": [
        "participle",
        "present"
      ]
    },
    {
      "form": "keyed off",
      "tags": [
        "participle",
        "past"
      ]
    },
    {
      "form": "keyed off",
      "tags": [
        "past"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "*"
      },
      "expansion": "key off (third-person singular simple present keys off, present participle keying off, simple past and past participle keyed off)",
      "name": "en-verb"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        "English terms with usage examples",
        "en:Computing"
      ],
      "examples": [
        {
          "text": "This logic keys off the user's social security number.",
          "type": "example"
        }
      ],
      "glosses": [
        "To take something as a controlling input datum."
      ],
      "links": [
        [
          "computing",
          "computing#Noun"
        ]
      ],
      "raw_glosses": [
        "(computing) To take something as a controlling input datum."
      ],
      "topics": [
        "computing",
        "engineering",
        "mathematics",
        "natural-sciences",
        "physical-sciences",
        "sciences"
      ]
    },
    {
      "categories": [
        "English terms with usage examples"
      ],
      "examples": [
        {
          "text": "She keyed off the ignition and went into the house.",
          "type": "example"
        }
      ],
      "glosses": [
        "To turn off something (e.g. a car) using a key."
      ],
      "links": [
        [
          "turn off",
          "turn off"
        ]
      ]
    }
  ],
  "word": "key off"
}