Terminology

One-to-one call

A One-to-one call is a call made between two users. Each user is identified by an address which can be a telephone number. In a typical interface you select a contact from list and press the PTT button to initiate a one-to-one call. Later on you can add more participants to the call if necessary.

Adhoc group

An ad hoc group call is similar to a one-to-one call but has more than two participants. An ad hoc group is formed when multiple PoC users are selected from the contact list and the call is started. Each of the selected users is invited automatically into the PoC call. An ad hoc group is temporary so the member list is not stored in the network. The group will disappear when the call ends, or alternatively when the user quits the PTT application.

Pre-arranged group

A pre-arranged group, also known as dial-out group, is a permanent group with a predefined list of members. The group is identified by a unique address. When any of the group members starts a call to a pre-arranged group, all the other members will be automatically invited to the call.

Unrestricted chat

Unrestricted (Open) chat groups are like chat rooms, discussion forums, and two-way radio channels. PTT users can join/leave the chat groups whenever they like, and the main difference to a pre-arranged or ad hoc group is that joining a chat group does not invite any other users automatically. An unrestricted chat group does not have a predefined member list and anyone can join the chat group “call”.

Restricted chat

Restricted chat groups have a predefined list of members who can join the chat group call. Unlike in pre-arranged and ad hoc groups, joining a chat group does not automatically invite the other members. Only the creator of a chat group can modify the list of group members. If permitted by the group policy, members of the group can invite more participants to an ongoing call, as long as the invited participant is a member of the group. The permission to invite more users can be given by the creator of the group.

Presence

A presence service allows users to instantly see who is online and willing to communicate. It complements other services such as push-to-talk by showing whether the people on a contact list are available for communication or if they are offline or busy. The service can also show more detailed status information about the users, such as their activity, location and service capabilities.

Abbreviations