Alpha Number to Digits

    function alpha2phone(alphastring)
    {
        var retArr = [];
        alphastring = alphastring.toUpperCase();

        for(var i = 0; i < alphastring.length; i++)
        {
            retArr.push(alpha2num(alphastring.charAt(i)));
        }
        retArr.splice(-4, 0, '-');
        return retArr.join('');

        function alpha2num(n)
        {
            var arr = ['0','1','ABC','DEF','GHI','JKL','MNO','PQRS','TUV','WXYZ'];

            for(var j = 0; j < arr.length; j++)
            {
                if(arr[j].indexOf(n) > -1)
                {
                    return j;
                }
            }
            return n;
        }
    }

    console.log(alpha2phone('1-800-SIMPSON'));