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CDD-880 Multi Receiver Router
Appendix B
?
(ASCII code 63)
2. From Target-to-Controller, the only permitted values are:
Symbol
=
(ASCII code 61)
?
(ASCII code 63)
!
(ASCII code 33)
*
(ASCII code 42)
#
(ASCII code 35)
B.4.6
Optional Message Arguments
Arguments are not required for all messages. Arguments are ASCII codes for the characters 0 to 9 (ASCII codes 48 to 57), period (ASCII
code 46) and comma (ASCII code 44).
B.4.7
End of Packet
Controller-to-Target: This is the 'Carriage Return' character (ASCII code 13).
Target-to-Controller: This is the two-character sequence 'Carriage Return', 'Line Feed' (ASCII codes 13 and 10). Both indicate the
valid termination of a packet.
The '?' code is used as the Query Operator (QO) and is used to indicate that the Target should return the current value of
the parameters defined by the preceding byte.
Example: In a message from Controller-to-Target, IG1? Would mean "return the current value of the GE Port IP address."
The '=' code is used in two ways:
a. If the Controller has sent a query code to a Target (Example: CMD? meaning "what's the value of this parameter?"), the
Target would respond with CMD=xxx, where xxx represents the parameter in question.
b. If the Controller sends an instruction to set a parameter to a particular value, then, providing the value sent is valid, the
Target will acknowledge the message by replying with CMD=(with no message arguments).
If the Controller sends an instruction to set a parameter to a particular value, then, if the value sent is not valid, the Target
will acknowledge the message by replying, for example, with CMD? (with no message arguments). This indicates that
there was an error in the message sent by the Controller.
If the Controller sends an instruction code which the Target does not recognize, the Target will acknowledge the message
by echoing the invalid instruction, followed by the ! character. Example: CMD!
If the Controller sends an instruction to set a parameter to a particular value, then, if the value sent is valid, BUT the
modulator will not permit that particular parameter to be changed at this time, the Target will acknowledge the message by
replying, for example, with CMD* (with message arguments).
If the Controller sends a correctly formatted command, BUT the unit is not in remote mode, it will not allow reconfiguration
and will respond with CMD#.
Definition
B–4
Revision 0
MN-CDD880
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