SDM-6000 & SDM-8000
Compatibility with
Redundancy Switches
Application Note
Overview
The SDM-6000 Satellite Modem is a low-cost alternative to the SDM-8000 Satellite Modem. The SDM-8000 supports
additional remote control parameters and higher data rates than the SDM-6000; therefore, the SDM-6000 is not a
replacement for the SDM-8000.
Minor complications can occur in establishing a redundant switch system when the Prime and Backup modems are not the
same model number and equal in capability. The Comtech EFData redundancy switches, such as the SMS-658, SMS-758,
and SMS-7000, use the remote control parameters in each of the Prime and Backup modems for controlling the Backup
modem in the event of a Prime modem failure. Prior to the Backup modem being placed ‘ON-LINE’ for a failed Prime
modem, the switch will verify the backup modem can fully protect the failed Prime modem. If there is a failure to
communicate with the Backup modem, or the capability of the Backup modem does not equal or exceed that of the Prime,
the switch will declare an alarm and not switch the Backup modem ‘ON-LINE’.
Since the initial release of the SDM-8000, Comtech EFData has created additional tools within the 'UTILITY - MODEM
TYPE' menu in most of the modem products that will allow various combinations of modems to be mixed within a
redundancy switch system. These tools include:
•
The REV EMULATION menu – used by any new Prime modems to emulate previous firmware revisions so that the
operating parameters of the Backup modem can be matched. This is helpful because the operator can add to an
existing redundancy system without disrupting the current setup.
•
The MODEM TYPE COMPATIBILITY menu – used to add, for example, an SDM-8000 as a Prime modem into a
redundant switch system with an SDM-308 or -309 serving as Backup modem. Care must be taken in this situation,
because not all of the SDM-308 and -309 versions are supported. In the modem installation and operation manual,
refer to the Configuration chapter and the Modem Emulation section for information on the specific versions of each
product that the MODEM TYPE COMPATIBILITY function will support.
Comtech EFData Recommendations
As stated above, the SDM-8000 supports additional remote control parameters and higher data rates than the SDM-6000.
In a redundancy switch system with a mix of SDM-6000 and -8000 modems, the SDM-8000 must be installed as the
Backup modem. Additionally, compatibility between the various modems’ software versions must be evaluated. Use the
following chart to assist in evaluating the modem software versions:
Compatibility Chart
SDM-8000 Backup
SDM-6000 Prime
9.x.x and below
All versions
Not compatible.
10.x.x
All versions
Will not support ASYNC. Will not support D&I or IBS unless the backup
has an Interface Relay Card installed.
11.x.x and 12.x.x
All versions
Will not support D&I or IBS unless the backup has an Interface Relay
Card installed.
13.x.x and above
2.x.x and above
Compatible.
Copyright 1999 Comtech
EFData Corporation
Compatibility
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July 26, 2000
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Comtech EFData
2114 West 7th Street
Tempe, Arizona 85281 USA
(480) 333-2200
Fax: (480) 333-2540
WebSite: http://www.comtechefdata.com
Comtech EFData reserves the right to make changes to specifications of products described herein at any time without notice and without obligation to notify any person of such changes.
Comtech EFData Application Note
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(Part Number APN/SDM6/8COMPAT) July 26, 2000
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