CRS-300 1:10 Redundancy Switch Revision 16
Modem, RMI/TMI, and Switch Configuration MN/CRS300.IOM
5–8
5.2.4.5 Switch to CDM-Qx/QxL Redundancy Configuration
The CRS-300-to-CDM-Qx/QxL redundancy configuration uses an external EIA-485 multi-drop
communication cable.
The CDM-Qx/QxL can be configured many different ways, such as one to four modulators, or
one to four demodulators, or a mix and one or modems. For a CRS-300 application, the
CDM-Qx/QxL should be configured only as one modem: containing one modulator and one
demodulator card, which must be grouped to act as a modem. See the CDM-Qx/QxL Installation
and Operation Manual for more information.
As shown in Figure 5-1, Modem 1 resides in Slots 1 and 2. Modem 2 is contained in Slots 3 and
4. The Switch can use either modem.
(a) Front Panel
(b) Rear Panel Schematic
Figure 5-1. CDM-Qx/QxL Serial Communication Configuration
The CDM-Qx/QxL chassis has a configurable EIA-485 (referred to on the menus as RS-485) base
address – which applies for Modem 1 – and an offset, which is added to the base-address if
addressing Modem 2. The RS-485 addresses are selected via the front panel menu: CONFIG Æ
REMOTE.
The Switch addresses each CDM-Qx/QxL modem based on which TMI it is attached to, with
addresses at increments of 100. For a Switch with address 0, a Qx on TMI 1 has address 0100, on
TMI 2 address 0200, etc to address 1000 for TMI 10. The RMI uses address 1100. See Figure
5-2 and Appendix B. ADDRESSING SCHEME INFORMATION for more information.
Once the addressing scheme is understood, proceed as follows:
Step Procedure
1 Configure COMs on each modem via the modem front panel menu as follows:
CONFIG Æ REMOTE: RS-485-4W, 9600 baud, format 8-N-1.
2 Set the RS-485 (EIA-485) base address and offset, per Appendix B. Addressing
Scheme Information.
Refer to the CDM-Qx Installation and Operation Manual for detailed configuration information.
Modem 1
Modem 2
Status Indication
Slot 1 Mod
Slot 2 Demod
Slot 3 Mod
Slot 4 Demod IF I/OPrime Power & Control