Datum Systems M7 Series, Инструкция по установке и эксплуатации

Страница: 32 / 190

Operation M7/M7L/M7LT Modular Satellite Modem
1-26 M7/M7L/M7LT - Rev. 0.05
1.7. M7 Series Feature Sets
Feature Sets create specific capabilities that configure the modem parameters to fit a particular
application. Selection of modulation type, FEC type, and data rate ranges are the components of a
Feature Set. Using the Feature Set capability allows the purchase of the lowest cost configuration
that fits the current application without sacrificing future advanced capability. There are three (3)
feature sets offered for the modem which apply to any of the IF variations. More detail on maximum
and minimum data rates are shown in Appendix A.
Table 1-5 - M7 Series Feature and Option Matrix.
Feature M7 M7L M7LT
Model # Model Model Model
NOTE: Table is TBD
1.8. 1:1 Redundancy Function (Future Option)
The modem is capable of operating in a 1:1 redundancy protection mode without the use of a
separate redundancy switch controller. Three (3) components are required to be external to the two
(2) modems configured for 1:1 operation.

a combiner at the transmit IF

a splitter at the receive IF

a “Y” cable at the terrestrial data connection
With this connection scheme the switching is only performed on the outputs from the modem. The
modem IF and data inputs are always available at the modem allowing internal circuitry to determine
if one modem is correctly ac
cepting and “locking” to the input signals while the other is unable to if in
a failed state.
The two (2) modem
s operate in a “non-priority” redundancy mode, that is, no modem is specified as
“primary”, or having preference when both modems are operational. The first modem turned on
assumes a non-redundancy mode until the second connected unit is powered up. The on-line unit
can be set to send its configuration information to a second unit via the front panel. The modems will
remain in this state, constantly sending status information back and forth until one unit indicates a
failure. If that modem is currently on line, it is switched off-line and the alternate unit is switch on.
The alarms that are used to determine switching criteria are programmable, and the first modem set
up for this mode automatically loads its configuration information to the second or “alternate” unit.
These features create a very low cost redundancy system that is both flexible and easily set up.
The modem is also capable of operating in 1:N and M:N redundancy switching schemes. The
necessary connections to monitor and control switching are available on the data connector itself in
the form of the modulator and demodulator fault outputs and the auxiliary RS-232 control port. The
alarm outputs are also available. The other facility provided to aid in these redundancy schemes is
the ability to save and recall configuration information. Thus a back-up modem can obtain and save
the configurations from 8 other modems and switch immediately to the necessary parameters to
replace any of those units by simply recalling that unit’s stored configuration. In addition, the
programmable interface and common physical data connector allows different interface protocols
between the primary modems.
More information on the set-up and use of the 1:1 redundancy functions and modes is given in
Section 3.14 - Built-in 1:1 Redundancy Mode Operation.