Comtech EF Data CRS-200 - Manual (Page 64)

Remote Control CRS-200 Redundancy Switch
B–4 Rev. 1
B.5.2 Address
While up to 9,999 devices can be uniquely addressed, connection to the 1:N Redundancy
Switch imposes some basic limitations. In EIA-232 applications the switch’s “base
address” must be fixed at 0000. The 11 modems that may be connected to it can be
accessed via the switch at addresses 0100 (for Traffic Modem #1), 0200 (for TM #2) and
on up to 1000 (for TM #10) and 1100 (for the Redundant Modem). Valid remote
commands and queries which can be sent to the modems via the switch depend upon the
modem model number used.
Please consult the manual for the modem being used. There are similar restrictions on
address selection for distant-end units (being accessed by EDMAC) and Comtech
ransceivers, connected either locally or at the distant-end of a link. Please consult the
SatMac help file for more details.
In EIA-485 applications, the same indexing of the modems based on the switch’s address
still applies. Now, however, the switch itself may be set to 1000, 3000, 5000 or 7000.
This allows up to 4 switches to be connected on the same bus. For example, if the base
address of the switch is set to 5000, the address of TM #3 is 5300. Note that in either
EIA-232 or EIA-485 mode the internal link from the switch to all the modems connected
to it is fixed at EIA-232.
This means that the modem addresses (0100-1100) do not have to be set on each modem.
Since they are in EIA-232 mode, their addresses stay at 0000. Commands are routed by
the switch to the appropriate modem based on the position of its TM Interface. Important
note: 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.
B.5.3 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, TFQ is for transmit frequency, 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).
IMPORTANT NOTE:
Comtech’s SatMac software (Version 2.3 or higher) is configured to monitor and
control a CRS-200 Redundancy system. For ease of configuration, the SatMac
software auto-configures the addresses of all devices (Modems and Transceivers)
defined within a system. The SatMac help file contains more details of address
restrictions