Signature; Subscription; Notifications About The Changes Of The Properties; Legend For The Control Commands - Lightware MX2-8x8-HDMI20-L User Manual

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7. LW3 Programmers' Reference
8.2.7. Signature
DEFINITION: The signature is a four-digit-long hexadecimal value that can be optionally placed before
every command to keep a command and the corresponding responses together as a group.
Each line is terminated with a carriage return (Cr, '\r') and line feed (Lf, '\n') characters. In several cases the
number of the lines in the response cannot be determined in advance, e.g. the client is intended waiting for the
whole response and also wants to be sure, that the received lines belong together and to the same command.
In these cases, a special feature the 'signature' can be used. In these cases, the response to that particular
command will also be preceded by the signature, and the corresponding lines will be between brackets:
Ý 1700#GET /EDID.*
Ü {1700
Ü pr /EDID.EdidStatus=F89:E1;D1:E2;D1:E3;D1:E4;F89:E5
Ü m- /EDID:copy
Ü m- /EDID:delete
Ü m- /EDID:reset
Ü m- /EDID:switch
Ü m- /EDID:switchAll
Ü }
INFO: The lines of the signature are also Cr and Lf terminated.
8.2.8. Subscription
DEFINITION: Subscribe to a node means that the user will get a notification if any of the properties of the
node is changed.
A user can subscribe to any node. These notifications are asynchronous messages and they are useful to
keep the client application up to date, without receiving any unwanted information. When the user does not
want to be informed about the changes anymore, he can simply unsubscribe from the node.
ATTENTION! The subscriptions are handled separately for connections. Hence, if the connection is
terminated all registered subscriptions are deleted. After closing a connection the subscribe command
has to be sent in order to get the notifications of the changes on that connection.
Subscribe to a Node
Ý OPEN /MEDIA/VIDEO
Ü o- /MEDIA/VIDEO
Get the Active Subscriptions
Ý OPEN
Ü o- /MEDIA/VIDEO
Ü o- /EDID
Ü o- /DISCOVERY
MX2-HDMI20 series – User's Manual
Subscribe to Multiple Nodes
Ý OPEN /MEDIA/VIDEO/*
Ü o- /MEDIA/VIDEO/*
Unsubscribe from a Node
Ý CLOSE /MEDIA/VIDEO
Ü c- /MEDIA/VIDEO
Unsubscribe from Multiple Nodes
Ý CLOSE /MEDIA/VIDEO/*
Ü c- /MEDIA/VIDEO/*
8.2.9. Notifications about the Changes of the Properties
When the value of a property is changed and the user is subscribed to the node, which the property belongs
to, an asynchronous notification is generated. This is notification is called as the 'change message'. The
format of such a message is very similar to the response for the GET command:
Ü CHG /EDID.EdidStatus=F48:E1
A Short Example of How to Use the Subscription
There are two independent users controlling the device through two independent connections (Connection #1
and Connection #2). The events in the rows occur after each other.
Ý OPEN /MEDIA/VIDEO/QUALITY
Ü o- /MEDIA/VIDEO/QUALITY
Ý GET /MEDIA/VIDEO/Quality.QualityMode
Ü pm /MEDIA/VIDEO/QUALITY.QualityMode=graphic
Ý GET /MEDIA/VIDEO/Quality.QualityMode
Ü pm /MEDIA/VIDEO/QUALITY.QualityMode=graphic
Ý SET /MEDIA/VIDEO/Quality.QualityMode=video
Ü pw /MEDIA/VIDEO/QUALITY.QualityMode=video
Ü CHG /MEDIA/VIDEO/QUALITY.QualityMode=video
Explanation: The first user (Connection #1) set a subscription to a node. Later the other user (Connection #2)
made a change, and thanks for the subscription, the first user got a notification about the change.
8.2.10. Legend for the Control Commands
Format
<in> Input port number
<out> Output port number
<port> Input or output port number
<loc> Location number
<parameter> Variable, which is defined and described in the command
Batched parameters: the underline means that more expressions or parameters can
<expression>
be placed by using a semicolon, e.g. I2;I4;I5 or F27:E1;F47:E2
Sent command
Ý
Received response
Ü
· Space character
54
}
Connection #1
}
Connection #2
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Connection #1
Description