Attero Tech SquawkBox - Manual (Page 14)

SquawkBox
User Manual
 Attero Tech LLC 2014 Page 10 614-00007-04
To override one or more groups of units, use a general override but broadcast to all units using an appropriate broadcast
destination IP address. This is achieved by leaving the Tag field empty (just send NULL’s) and including a group mask. The
group mask must contain at least one active group for the override to activate.
To target a single unit, use a general override but target the UDP packet to a specific devices IP address ensuring that the
group mask sent matches at least one of the groups in the unit it is being sent to. Using a single unit override requires the
application starting and stopping the override knows the IP address of the unit concerned. If each device has a static IP
address, this is not a problem but if dynamic IP addresses are used, a device’s IP address may change periodically. The
application will therefore need to obtain the devices IP address from its MAC address which is unique and never changes.
*Note:
It is possible to activate overrides on multiple units by sending multiple override requests to individual units.
When the packet is received, a unit will go into override if
1. The tag is set to EMERGENCY
or
2. The tag is empty and at least one group mask bit matches the units own group mask.
5.3.1 – Substitute Override Settings
The UDP packet sent can also include additional data that allows the default override settings to be replaced. The following
additional fixed length fields may also be included in the packet following the Tag field.
Field Type Description
Bundle 16-bit Bundle number. A value of 0 defaults to the units override bundle number
Submap 8-bit Value between 1 and 8. A value of 0 defaults to the units override submap
Volume 8-bit Value between 1 and 20. A value of 0 defaults to the units override volume
Override Name 16 char A null terminated character string. Sending just a null will default to the units own override
name
The additional data, if non-zero, is used as a substitute for the devices own override settings. If these values are not sent or
they are set to zero, the unit will use its own override default settings.
5.3.2 – Exiting Override
All units that go into override mode will remain in override mode until they receive a second UDP packet with both a blank
tag and group mask set to 0. Any other data added is ignored.
*Note:
Although it is possible to activate the override on multiple SquawkBoxes simultaneously using multiple override
messages, it should be noted that any unit receiving the stop packet will drop out override irrespective of what packet was
used to force it into override initially.
5.4 – Overrides and IP addresses
In order for the override to work, each SquawkBox must be assigned an IP address. The IP address can be statically or
dynamically assigned.
Assigning a static IP address is done by setting the static IP address parameter on each unit. A static subnet mask must also
be configured. Each SquawkBox must have a unique static IP address on a network and all the addresses must be on the
same subnet for the overrides to work.
*Note: Retention of a static IP address is subject to persistence being active. If persistence is turned off, any static IP
address will be lost if the SquawkBox is reset or turned off.