In which country is your Diners Club card issued? The transfer rates are published in the online redemption catalog. Canadian and USA cardholders must login to see this information.
In the USA program the airline transfers are 1000:1000 for those programs denominated in "miles". It varies for airlines which use points or other units. The hotel transfers are in multiples of 1250, ranging from a low of 1250:750 for Hyatt and Starwood to a high of 1250:3300 for Best Western.