Comtech EF Data CRS-300 - Manual (Page 28)

CRS-300 1:10 Redundancy Switch MN/CRS300.IOM
Introduction Revision 19
1–2
The CRS-300 is intended for hub applications. It is compatible for use with the Comtech EF Data
modems specified in Table 1-1. While the Switch is capable of controlling any of these modems,
note that it is important that only one type of modem may be connected to the Switch within a
given redundancy system; this is because the Redundant Modem must operate identically to the
configured Traffic Modem.
A key feature of the CRS-300 architecture is its ability to allow the Redundant Modem to ‘bridge’
a Traffic Modem. The Switch automatically configures the Redundant Modem to match the
bridged modem’s configuration. The Switch also copies the bridged modem’s terrestrial transmit
clock/data and routes it to the Redundant Modem.
When used with the CRS-280/280L, the CRS-300 additionally routes the bridged modem’s Rx IF.
Because this live traffic is used at all times to verify performance, no external test equipment is
needed to determine the health of the Redundant Modem.
Construction features – The CRS-300 is modular in construction – all replaceable modules
install into slots in the back panel. This includes the controller, Redundant Modem Interface
(RMI), Traffic Modem Interfaces (TMIs), and Power Supply Units (PSUs).
Because power consumption is below 30 watts for a fully populated Switch, the CRS-300
requires no fan cooling.
Key Reliability Features – The CRS-300 incorporates the following key reliability features:
• Dual, independent, AC or DC power supplies.
• Traffic Modems with differing data types can all be supported by the Redundant Modem –
the exception to this is the CDM-Qx/QxL and, with some limitations, the CDM-625/A.
• Primary traffic paths are maintained, error-free, when power is removed.
• TMIs can be completely removed from the CRS-300, with cables still attached, and traffic is
not interrupted or affected.
• RMI and/or TMIs can be replaced without disturbing other traffic circuits.
Interfaces – The CRS-300 supports all of the modems’ available interface types. This includes
EIA-530/-422, V.35, Sync EIA-232, ASI, Balanced or Unbalanced G.703, LVDS, Single-port
Ethernet Bridge Mode, and HSSI.
Ease of Connection – The modular design of the Switch simplifies cabling connections between
the Switch and the Redundant and Traffic Modems, thereby reducing the number of potential
failure points within the rack enclosure installation:
• When you use the CDM-625/A, CDM-570/A, CDM-570L/AL, or CDM-600/L modems – T he
multi-protocol interface requires only a single cable for each modem. This cable carries all
data signals, alarm information, and the serial remote control interface.