The default country code is an extra piece of validation which is checks to ensure that a pre-specified dialling code is included within the MSISDNs of each recipient.
So, for example, if the default country code has been set to 44 (i.e. United Kingdom), the same recipient number could be given in any of the following formats:
The default country code should only be used by customers who terminate messages in one single country on a frequent basis.