Docs Broadcasting

Zones

A zone is a group of receivers taking the same broadcast. NOT Cable is not limited to sending one broadcast to every point: several playlists or streams can run from the same Studio, and each zone can play one of them.

A calm list in the lobby, another stream at the terrace cafe, an up-tempo list in the gym, silence in the stock room. All of it is managed from one panel, on one machine.

One Studio, three zones. Each zone has its own broadcast, but the clock is shared.

In sync within a zone, one clock across zones#

Every receiver in a zone plays the same broadcast at the same instant. That is the basic behaviour of the system.

Zones playing different music does not disturb that, because there is only one clock. Each zone's broadcast engine shares the main source's clock and does not serve one of its own. Zones therefore play different music while sitting on the same timeline.

The practical consequence: a receiver that changes zone does not have to lock again. Its clock is already correct; only the broadcast it listens to changes.

How many zones?#

There are sixteen zones, 0 through 15. Each has its own multicast group, and the address is derived from the zone number.

Zone 0 is the default group, 239.255.77.77. A newly started receiver joins that one.

Separate addresses mean the zones are genuinely separate on the network too. A zone's broadcast never reaches another zone's receiver, so nothing has to be filtered at the receiver and no needless traffic is produced.

Moving a receiver into a zone#

A receiver's zone is changed while the broadcast runs. Studio sends a small control packet; the receiver leaves the old group and joins the new one.

The moment it joins it adopts the new zone's stream as it stands. The stream id may differ and the receiver does not mind: it starts playing from where the zone is, not from where it left off.

Nothing has to be done at the receiver itself, no restart and no setting.

What it is for#

A few typical uses.

A multi-floor store. A separate broadcast for the women's, men's and children's floors. Each floor plays to its own customer, and the list upstairs does not affect the ground floor.
Hotels and venues. Lobby, terrace cafe and gym play three different lists at the same time. The lobby stays calm while the gym stays up-tempo.
Separate areas. A cafe, a restaurant or fitting rooms take their own broadcast, apart from the rest of the venue.
A silent zone. A stock room, an office or a meeting area gets nothing at all.
Testing by zone. A new list is tried in one zone first, without affecting the whole venue.

One point of management#

All of this is run from a single Studio screen. As the number of zones grows, the number of machines to manage does not: lists, streams, receivers and zones all sit in the same place.

The same holds on the network. Because each zone uses its own multicast group, the broadcast is sent once per zone and is not multiplied by the number of receivers. See Network requirements for detail.

For listing, silencing and setting the level of receivers, see Managing receivers.