Edit in JSFiddle

var contactData = [
    {firstName: 'John',lastName: 'Doe',phone: '1-111-1111'}, 
    {firstName: 'Jane',lastName: 'Doe',phone: '2-222-2222'}
];

//create a collection from model constructor and data
var contacts = new Backbone.Collection(contactData,{model:Backbone.Model});

console.log(contacts.toJSON());

/*above logs: 
[{firstName="John", lastName="Doe", ...}, {firstName="Jane", lastName="Doe", ...}]*/