A 100 Number DID (Direct In Dial) Range is a series of 100 numbers that are allocated to ISDN Business phone lines.. Even though you may only have 2, 4, 6 or 10 or more ISDN phone lines connected, you can be allocated a block of 100 numbers and this is known as a 100 number DID range.

100 Number DID ranges are a batch of 100 numbers starting with 00 and ending in 99. For example 0265641200 to 0265641299.

The main benefit of using a 100 number Direct In Dial range is that you dont need to have a full phone line for every employee. Using a DID range also means you can have multiple generic numbers allocated to departments such as accounts, sales, service etc as well as direct numbers for any employees needing them.

When a 100 number DID range is combined with PABX phone system functions such as line hunt and pre programmed call orienting are possible.

For example if you allocated a number for accounts, the DID range can be programmed on the PABX phone system to forward incoming phone calls to a nominated batch of extensions for that department, and then to hunt through those extensions until a free extension is available. In simple terms the call can hunt around the department until it finds an employee who is not on the phone and able to take the call.

Most networks that offer ISDN Digital business phone lines (available with ISDN 2 and ISDN 10/20/30) will be able to offer a 100 Number Indial range.