BT Versatility: ring groups and DDI numbers

BethM — Mon, 03 Aug 2026 14:26:53 GMT

The BT Versatility phone system is no longer supported by BT Business. Support ended on 30 September 2025, and we won't update this page if anything changes with the product.

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We've brought our BT Versatility ring groups and DDI help together in one post. It covers how ring groups work, group mailboxes, hunt groups, and DDI and MSN numbers.

Ring groups

There are 20 ring groups, and they can be used in any order (groups 11 to 20 work slightly differently - see below).

Allocate the extensions you want to ring in a group for incoming or internal calls. You can program between 1 and 16 extensions in each group.

By default, group 1 is programmed with extensions 20 to 27 - so the default ringing mode for all lines rings extensions 20 through 27. All other groups are programmed with extension 20 only. Extensions can be in more than one group, but every group must have at least one extension.

Each group has a unique number: group 1 is 180, group 2 is 181, and so on up to group 20, which is 199. These can be called internally, or calls transferred to them, using the group number. DDI numbers can also be programmed to ring a group.

Group mailboxes. If a group has a mailbox enabled, you can program calls on busy, no answer, or all group calls to route to the mailbox. The group mailbox numbers are the same as the group numbers (180 to 199).

Hunt groups. Extensions can be programmed into hunt groups. Instead of ringing all the extensions at once, you can program three types of call routing: linear, cyclic, and longest idle. Extensions must log in to the hunt group. Extensions can also be assigned to call pick-up groups to answer ringing extensions.

An example Group 5 has extensions 24 and 27, with line 2 assigned. When line 2 receives an incoming call, extensions 24 and 27 ring together if they’re free. If extension 31 in the same office wants to answer this call, create a new spare group with extensions 24, 27 and 31 assigned. This new call pick-up group lets extension 31 answer the call by selecting call pick-up or dialling the pick-up code.

Groups 11 to 20 have an extra feature: they can be used as options on an Auto Attendant. So if calls route to an Auto Attendant and options 1 to 3 are groups 20 to 18, assign the extensions to each of those groups. Remember, extension 20 is assigned to each of the 20 groups by default.

DDI and MSN numbers

Direct Dialling In (DDI) or Multiple Subscriber Numbering (MSN) lets callers dial through to a particular extension without speaking to the switchboard operator.

DDI/MSN can route to either:

a single extension (for example, a fax extension), or
a ring group, Auto Attendant or Courtesy service.

MSN/DDI numbers can show the Calling Line ID (CLI) of the caller. Up to 100 DDI numbers can be programmed, each with an index from 01 to 100.

For programming, see pages 53 to 56 and 99 to 100 of the Owner’s Manual.

topic BT Versatility: ring groups and DDI numbers in Phone system

BT Versatility: ring groups and DDI numbers

Ring groups

DDI and MSN numbers