How many days of information do you have? If it is for 1 month, then
you will have 30 (or 31) times 48 cells of derived data. Do you want
this organised as a table of 48 cells across by 30 down, or as a list
of nearly 1500 cells in one column, or are you only interested in the
arrivals by half hour blocks for the consolidated month?

I assume you have date and time data for each call - are these in
separate columns or combined into one column?

You should be able to use the COUNTIF( ) function, but details of how
to use it will vary depending on the exact nature of your data and how
you want the output to appear.

Hope this helps - post back with further details if you require further
help.

Pete