Reference
  TNC Settings

Broadcast messages are messages sent simultaneously to all members of a group. To send a broadcast message press the Broadcast button on the Main Screen to open the Broadcast screen. FNpack lets you belong to up to six different groups at the same time as shown in the figure. To change from these names to the names of your groups use the SetupGroups menu item.

Broadcast messages are sent using the "unproto" packet format with the entire message in a single packet. The unproto packet is addressed to the group name so all stations using FNpack software with that group name will accept the packet as a received message.

The unproto packet format is connectionless; that is, connections are not set up with each destination station. Unproto packets make efficient use of the radio channel. A single transmission can be received simultaneously by all stations with the same group name. The disadvantages are 1) the sending station cannot tell which stations are actively listening when the message is sent, and 2) the sending station may not know if interference corrupts a transmitted packet.

Unproto packets can be relayed through intermediate stations by digipeating. The first group name initially configured in FNpack is "SGNET V WB1BRE" which means that the message will be broadcast to the SGNET group via digipeater WB1BRE.

When broadcast messages are digipeated through a central node the originating station can tell if the message is corrupted by interference because the originating station can monitor the packet relayed by the digipeater.