Something

SELECT
        (c.billsec/60) AS ttime,
        c.dst AS dest,
        UNIX_TIMESTAMP(c.calldate) as ctime,
        c.accountcode
FROM
        cdr c
WHERE
        c.lastapp = 'Dial'
AND  
        c.disposition = 'ANSWERED'
AND
        c.accountcode IS NOT NULL
AND
        c.src = 7099
AND
        (c.calldate BETWEEN FROM_UNIXTIME(1202256000) AND FROM_UNIXTIME(1202298498))