{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "definitions": {
        "Telecom": {
            "type": "object",
            "additionalProperties": true,
            "title": "Telecom schema.",
            "description": "An explanation about the purpose of this instance described by this schema.",
            "properties": {
                "value": {
                    "type": [
                        "string",
                        "null"
                    ],
                    "minLength": 1
                },
                "preferred": {
                    "type": [
                        "boolean",
                        "null"
                    ],
                    "minLength": 1
                },
                "use": {
                    "type": [
                        "string",
                        "null"
                    ],
                    "minLength": 1
                }
            }
        },
        "Contactable": {
            "type": "object",
            "additionalProperties": true,
            "allOf": [
                {
                    "$ref": "#/definitions/Telecom"
                }
            ]
        }
    },
    "properties": {
        "Telecom": {
            "$ref": "#/definitions/Telecom"
        },
        "Contactable": {
            "$ref": "#/definitions/Contactable"
        }
    },
    "required": [
        "Telecom",
        "Contactable"
    ]
}