Product specifications

CDD-562L/564 Demodulator with IP Module Revision 1
Appendix D MN/CDD564L.IOM
D–4
The Controller sends a packet with the address of a Target – the destination of
the packet. When the Target responds, the address used is the same address,
to indicate to the Controller the source of the packet. The Controller does not
have its own address.
D.3.4.3 Address Delimiter
This is the character ‘/’ (forward slash) (ASCII code 47).
D.3.4.4 Instruction Code
This is a three-character alphabetic sequence that identifies the subject of the message. Wherever
possible, the instruction codes have been chosen to have some significance.
For Example: TFQ for Tranmsit FreQuency; RMD for Receive MoDulation type, etc. This aids
in the readability of the message, should it be displayed in its raw ASCII form. Only upper case
alphabetic characters may be used (A-Z, ASCII codes 65 - 90).
D.3.4.5 Instruction Code Qualifier
This single character further qualifies the preceding instruction code. Code Qualifiers obey the
following rules:
1. From Controller-to-Target, the only permitted values are:
=
(ASCII code 61
The = code is used as the assignment operator, and is used to indicate that the
parameter defined by the preceding byte should be set to the value of the
argument(s) that follow it. For example: In a message from Controller-to-Target,
TFQ=0950.0000 would mean ‘set the Tx frequency to 950 MHz’
?
(ASCII code 63)
The ? code is used as the query operator, and is used to indicate that the Target
should return the current value of the parameter defined by the preceding byte.
For example: In a message from Controller-to-Target, TFQ? would mean ‘return
the current value of the transmit frequency’.
2. From Target-to-Controller, the only permitted values are:
=
(ASCII code 61)
The = code is used in two ways:
First, if the Controller has sent a query code to a Target (for Example: TFQ?,
meaning ‘what is the Tx frequency?’), the Target would respond with
TFQ=xxxx.xxxx, where xxxx.xxxx represents the frequency in question.
Second, if the Controller sends an instruction to set a parameter to a particular
value, and if the value sent in the argument is valid, then the Target will
acknowledge the message by replying with TFQ= (with no message arguments).
IMPORTANT