Direct Dial In numbers (DDIs) are additional numbers that allow calls to bypass the operator and be directed straight to the required extension. They are normally used with a PBX, providing separate numbers for individual staff. Your PBX is programmed to route incoming calls using DDI numbers to the correct extensions.
It is possible to order sets of DDIs (minimum purchase is 10 numbers). If an existing phone number is important to your organisation and you have ISDN30e, it is possible to set it up as a single-number DDI. This is not possible with ISDN30. To order, or find out the current connection and rental costs, contact Business Sales on 0800 800 152.