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CDM-Qx Satellite Modem
Remote Control
Common functions can be accessed through any of the four addresses. If several devices
share a RS-485 bus, it must be noted that the Qx will require four addresses, and should
be spaced apart accordingly. Empty slots in the Qx chassis still occupy an address.
IMPORTANT
C.4.3
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:
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).
C.4.4
Instruction Code Qualifier
This is a single character that further qualifies the preceding instruction code.
Code Qualifiers obey the following rules:
1.
They have these meanings:
The '=' code (controller-to-target) 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) which follow it.
For example, in a message from controller to target, TFQ=0950.0000 would mean 'set
the transmit frequency to 950 MHz.'
The '?' code (controller to target) 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, a message from the controller to target, TFQ? Would mean 'return the
current value of the transmit frequency.'
A single CDM-Qx occupies four addresses. For modulator and demodulator
grouped as modem, the address will be the same as the modulator.
TFQ for transmit frequency
RMD for receive modulation
From Controller-to-Target, the only permitted values are:
= (ASCII code 61)
? (ASCII code 63)
C-4
Revision 6
MN/CDMQx.IOM
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