Comtech EF Data CRS-400 - Manual (Page 79)

CRS-400 1:8 Redundancy Switch Revision 0
Remote Control MN/CRS400.IOM
63
Remote monitor and control of units attached to the Switch is available, transparently via
the Switch, to any devices with addresses x001 through x099, attached to the auxiliary
EIA-485 link. The command protocol of the messages is dictated by the device being
addressed.
Note that in either EIA-232 or EIA-485 mode, the auxiliary link from the switch to all
the modems is fixed at EIA-485, 8-N-1, 19200 baud (multidrop).
The modem addresses (001-019) must be set on each mod/demod, via the front panel.
Example: To send a message to TM# 1 (front panel address set to 001) attached to the
multidrop cable of switch (address 5000), the controller sends a message using address,
5001, and the responses from the modulator (via the switch) will indicate address 5001.
B.5.3 I
NSTRUCTION
C
ODE
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, OPM is for OPerating Mode, BKH is for BacKup Holdoff, etc. This aids in
the readability of the message if seen in its raw ASCII form. Only upper case alphabetic
characters may be used (A-Z, ASCII codes 65 - 90).
B.5.4 I
NSTRUCTION
C
ODE
Q
UALIFIER
This is a single character that 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)
? (ASCII code 63)
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) that follow it. For example, in a message from controller to target, OPM=1
would mean ‘set the OPerating Mode to Auto’
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, in a message from controller to target, OPM? would mean ‘what is the
current Operating Mode?’