How do I use IDD and what are the rates? Admin - Support January 29, 2019 01:47 Updated Follow If you have opted for the IDD call feature, dial: 1550 + the country code of the destination you’re calling + the local number Please visit our Business Voice webpage for the prevailing IDD rates. Related articles Can I choose or purchase a Business Voice number that I like? Business fix line Number Porting How do I check my Business Voice usage for the current month? Is there a limit to the amount of IDD calls I can make? Service Application / Request Forms Comments 0 comments Article is closed for comments.