What is Digital Radio Group Call and Private Call and All Call

Today let us talk some basic information on digital radio group call, private call and All call. When some hams new to DMR, and they dont know what is group call, and private call. when choose talk group. when choose private group.

The Group Call service definition from ETSI  Technical Specification.

Group Call provides voice call service between one individual user and a predetermined group of users.  All parties in the group can hear each other.The Group Call is initiated at the user level by selecting the desired group via a predefined selection procedure and then activating a mechanism to talk, such as pressing the PTT button.
The simple understanding is that the communication between a group that has more than 2 people. If you choose a group call type when creating communication contacts, and select the talk group to your working channel. That means when you transmit if other people who also select this group call, they will receive your signals and you can receive from them. 

Example diagram

Individual call service definition from ETSI  Technical Specification.

The private call provides voice service between one individual user and another individual user. 
The Individual Call facility is initiated at the user level by selecting the desired individual via a predefined selection procedure and then activating a mechanism, such as pressing the PTT button. 

The simple understanding is like two people communicate via a phone. One to one call. Only here use their DMR ID. 

Example diagram 

3. All Call Voice service definition from ETSI  Technical Specification.

The All Call Voice service provides a one-way voice call from any user to all users within the same system. Due to the large target audience, there is no call hangtime associated with this call-in repeater mode. This effectively ends the call at the end of the transmission. 
The All Call may be placed by the user with the simple pressure of the PTT button.

All call is not commonly used for radio enthusiasts, it is more suitable for commercial use, similar to broadcasting.
When setting up to all call, this channel can only transmit, cant receive, just like our broadcast, only send and not receive.
For example, in a company, if the leader wants to publish a message, the leader's radio can set up a All call, at this time he transmits all other radio can be received, even if someone accidentally presses the PTT button to transmit, will not interfere with the leader's transmit.
And All call has its unique ID 16777215.