Pro rata is the small charge that covers the gap between when you connect and when the billing cycle starts. Direct Telecom billing cycle begins on the first of every month.
Please be aware that you will be charged a pro rata amount for your plan for the days after connecting, before your first billing cycle starts. You will also be given a pro rata amount of data for this period. Depending on the service that has been contracted (such as ADSL), you will be invoiced the pro rata of the current month plus the complete upcoming month in advance.