Wegener Communications 6420 - Manual (Page 45)

iPump 6420 User’s Manual
www.wegener.com 800070-01 Rev B Chapter 3, Page 41
the receiver is unaffected by command execution (or the lack thereof). These
commands must often be synchronized to other external events. For example, a
closure arriving from a customer’s media automation system, requesting the play of a
commercial spot must cause a command to edge iPump6420s to insert a particular
file, to be aligned precisely with a network “avail” (local spot opportunity).
• Time-of-day commands: Non-addressed commands that signal the date/time to all
listening receivers. Receivers that must know the precise time will interpolate over
many such commands to maintain accurate TOD tracking.
• Satellite File download operations: A special command and functions to go with it
that allow the download of media files to edge receivers. This is discussed more
thoroughly in Section 3.3.
• HTTP File download operations: A special command to request that receivers
pull media file content from Compel, by HTTP, over the internet.
• Playlist build commands: Commands to build playlists on edge receivers who
support that function. Playlists are discussed more thoroughly in Section 3.4.2.
• Miscellaneous commands: Commands that affect the remote receiver state, but are
not retained in the Compel database. For example, a command to pipe a terminal
command to iPump6420 may be sent using the Compel SCRIPT TERMINAL
command.
• Scheduling commands: Commands to add or delete line items in receiver’s Local
Scheduler, where supplied. See the discussion following on Local Scheduler.
• Refreshes: Not formally a type of “command”. This is a special Compel function to
keep remote receiver settings equal to that specified in the Compel database. It uses
many receiver state commands to do this. There is an “immediate” version, where a
fairly complete refresh is done on command of a human user. And there is a
“background” version, where, as time permits, Compel will regularly and
automatically refresh edge receivers on a rolling basis.
Command Structure:
Compel commands are structured as Header, Sequence number, Address, Device,
Command, and Data fields. The Header may be a generic 4-character string, or it may be a
string unique to a customer. If unique, then it imposes special security measures on all listening
receivers, where the receiver’s own Compel header setting must match that of the Compel
messages to avoid going into Recovery Mode (see below). The Sequence number is the way the
Compel hardware tags each unique command, allowing them to be double-transmitted to avoid
data loss. Addressing will be discussed below. The Device is a general command grouping.
The Command is a specific command within that grouping. The Data field is interpreted by the
receiver based on the Device and Command.
Addressing Rules:
Except for the Time-of-Day commands, the receivers will only accept and execute those
commands that are addressed to them. They may be addressed by four different addressing
modes. One is the rarely-used command to “All”. The other is a command directly addressed by
unit serial number (though, in the Compel GUI, the user may direct the command by the
receiver’s unique name). The truly powerful addressing mode is by Group, where only receivers
who know themselves to be members of the addressed Group, will respond. The last mode,
which is not truly independent, adds on an additional requirement for an address match: This is
called Associated Audio. This last command, part of the complement of Extended Syntax