Product specifications

CDD-880 Multi Receiver Router Revision 1
Serial-based Remote Product Management MN-CDD880
6–3
6.2 Remote Commands and Queries Overview
6.2.1 Basic Protocol
InanEIA‐232configuration,theControllerdeviceisconnecteddirectlytotheTargetdeviceviaatwowire‐plus‐groundconnection.Alldata
is transmitted in framed packets as asynchronous seri al characters, suitable for transmission and receptio n to the Controller using a
universalasynchronousreceiver/tr an sm itt er(UART).Controller‐to‐Targetdataisca
rriedviaEIA‐232electricallevelsononeconductor,and
Target‐to‐Controllerdataiscarriedintheotherdirectionontheotherc onduc tor:
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• Controller‐to‐Target:TheControllerdevice(e.g.,theuserPC/CLI)isusedtotransmitinstructions(comm a nds)to–ortorequest
informationfrom(queries)–theTarge
tdevice(i.e.,theCDD‐880). 
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• Target‐to‐Controller:The Target,inreturn,only  transmitsresponse informationto theController whenspecifically directedby
theController.
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ForSerialRemoteControl,allissuedcommands(C ontroller‐to‐Target)requirearesponse(Target‐to‐Controller).This responseiseither
to return  da
ta that has been queried by the Controller, or to confirm the Target’s receipt of a command to change the Target’s
configuration.
6.2.2 Packet Structure
The exchange of information is trans mitted, Controller‐to‐Target and Target‐to‐Controller, in ‘packets’. Each packet contains a finite
numberofbytesconsistingofprintableASCIIcharacters,excludingASCIIcode127(DELETE).
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Inthis context,theCarriageReturnandLineFeedcharactersareconsideredprintable.Withoneexception,allmessag
esfromController‐
to‐Targetrequirearesponse–thiswillbeeithertoreturndatathathasbeenrequestedbytheController,ortoacknowledgereceptionofan
instructiontochangetheconfigurationoftheTarget. 
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