Most companies will have a listing of corporate directory numbers. This may also include all emergency service numbers and numbers that are frequently called. These directory numbers need to be maintained and updated. A staff champion will need to be assigned to this task and be fully responsible for handling directory numbers.
Details of all directory codes and country codes needed to make a trunk call must to be readily available. In some cases regularly dialled area codes could be permanently assigned to trunk lines for fast and easy accessibility
Staff need to be trained to read the directory numbers correctly some numbers might include the country code or others have a full number when on only the last 4 digits are used for internal calls, while others might need the '0' deleted when making a overseas call