Comtech EF Data CDM-570 - Manual (Page 355)

CDM-570/570L Satellite Modem with Optional IP Module Revision 12
Appendix D MN/CDM570L.IOM
D–5
2. From Target-to-Controller, the only permitted values are:
Symbol Function
=
(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 Transmit 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, then, providing the value sent is valid, the Target will
acknowledge the message by replying with TFQ= (with no message arguments).
?
(ASCII code 63)
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 TFQ? (with no message arguments). This indicates that there was an error in the message sent
by the Controller.
!
(ASCII code 33)
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: XYZ!
*
(ASCII code 42) 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 TFQ* (with
message arguments).
#
(ASCI code 35) If the Controller sends a correctly formatted command BUT the modem is in local mode, it will not allow reconfiguration and will respond
with TFQ#
~
(ASCI code 126)
If a message was sent via a local modem to a distant end device or ODU, the message was transmitted transparently through the local
modem. In the event of the distant-end device not responding, the local modem would generate a response.
Example: 0001/RET~ (indicating that it had finished waiting for a response and was now ready for further comms).
+
(ASCII Code 43)
This is similar to the = code (acknowledgement). However, the + code is used to indicate that a command has been accepted and
processed, but additionally indicates that some other configuration parameter has also been modified.
Example: Suppose Viterbi + Reed-Solomon, QPSK, Rate ½ is selected. Now, the modulation type is changed from QPSK to 16-QAM by
sending TMD=4. In this case, Rate 1/2 is no longer a valid code rate, and so it is automatically changed to the nearest valid code rate (Rate
3/4). The Target will therefore respond with TMD+.
^
(ASCI code 94)
The ^ code indicates that the modem is in Remote mode, so serial remote control is not possible. There are two exceptions to this:
• The LRS (Local/Remote Status) command is still active, and may be used to change the operating mode to local or to serial remote
control.
• For the CDM-570L, the FPL (Front Panel Lockout) command is active, and may be used to configure the Front Panel Lockout to be
“No lockout” or “Active.”