65 standard recommends a time interval for outputting the zeroith event information table eit i e eit 0 but provides no guidelines regarding eit 1 through eit 128 for the rating region table rrt the a 65 standard recommends a value only for the output frequency of rrt 1 and no recommendation is made regarding the output frequencies of any of the extended text tables etts under the a 65 standard it is left to the discretion of the operator of a psip data generation system to select the frequency of table output for the unmentioned tables the operator could specify an entry for each group of tables but that would be burdensome because it would require a total of over 500 entries a simple solution to the problem of unspecified output frequencies would be to set each type of table to the same output frequency but that creates a problem in that the guidelines for bandwidth specified by the a 65 standard would be exceeded a further consideration to solve the problem namely of how to insert the least amount possible of meta data into the dtv signal and yet still achieve an a 65 compliant dtv signal is how closely in time to the present moment does each table relate that is table types such as the eit describe event information up to two weeks into the future a user of an electronic program guide that receives such table types will typically want to view event information concerning only the next 24 48 hours users typically.