Comtech EF Data PCB-4000 - Manual (Page 53)

PCB-4000 1+1 Phase Combiner Revision 2
Serial Remote Control MN/PCB4000.IOM
5–5
5.2.2.5 Instruction Code
This three‐character alphabetic sequence identifies the subject of the message. Wherever possible, the instruction codes have been
chosen to have some significance. This aids in the readability of the message if seen in its raw ASCII form. Upper and lower case
alphabetic characters (i.e., A‐Z [ASCII codes 65‐90], and a‐z [ASCII codes 97‐122]) may be used.
5.2.2.6 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:
Symbol Definition
=
(ASCII code 61) ‘=’ 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: MUT=1 would mean 'enable the Mute function.'
?
(ASCII code 63)
‘?’ 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: MUT? Would mean ‘return the current state of the Mute function.’
2. From Target‐to‐Controller, the only permitted values are:
Symbol Definition
=
(ASCII code 61)
The = code is used in two ways:
First, if the Controller has sent a query code to a Target (for example: MUT? would mean ‘return the current state of the Mute
function’), the Target would then respond with MUT=x, where ‘x’ represents the state in question (1 being ‘enabled’, 2 being ‘disabled).
Second, if the Controller sends an instruction to set a parameter to a particular value, then, providing the value sent in the argument is
valid, the Target will acknowledge the message by replying with MUT= (with no message arguments).
?
(ASCII code 63)
The ? code is only used as follows:
If the Controller sends an instruction to set a parameter to a particular value, then, if the value sent in the argument is not valid, the
Target will acknowledge the message by replying (for example) with MUT? (with no message arguments). This indicates that there
was an error in the argument of the message sent by the Controller.