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BLACK BOX
®
2 of 3
09/13/2011
#11110
»
Make your system more reliable by
switching to a backup modem when
your primary link fails.
»
Minimize downtime and inconvenience.
»
Flexible—can perform either manual
or automatic changeover switching.
»
Front-panel LEDs show you system status
at a glance.
»
Supports rates as high as your RS-232
line can carry.
»
230-volt version available.
FEaturEs
Breakdowns in your data communication are always
inconvenient—and often expensive. Our
RS-232 Fallback Switch
gives you another way to get your vital data through with the
least amount of downtime.
By diverting the traffic from a primary modem to a backup
modem when the preferred communications pathway fails, the
RS-232 Fallback Switch
keeps your data flowing. And because the
switchover is fast, efficient, and highly reliable, you’re given that
extra bit of assurance that your essential information will be there
when it needs to be.
Ideal for switching your data from a dedicated leased-line
modem to a dialup modem when the leased line goes down,
the device switches all 12 leads that are normally required for
sync or async operation. What’s more, it can support data rates
as high as your RS-232 cable can carry.
Automatic or manual modes
The
RS-232 Fallback Switch
also gives you several switching
options, providing flexibility as your system requirements change.
You can operate the switch manually (physically switching between
modems as needed), but it also has two automatic modes of
operation: normal fallback (FB) mode and autoswitching (AS)
mode, which you can customize by setting jumpers inside the unit.
Preset to operate in FB mode, the switch normally communicates
with the modem attached to its PRIMARY connector. But, during
automatic operation, the
RS-232 Fallback Switch
also checks
constantly for the presence of a “trigger signal” on its ALTERNATE
connector. And if one is sensed—whether it’s DSR (Data Set Ready,
Pin 6), CTS (Clear To Send), or Carrier Detect (CD), depending on
which of these you select—it’ll switch to the modem attached to
that connector. (This switch occurs even if the primary modem is
still operating.) When the switch no longer senses the trigger signal,
it “falls back” to the primary modem.
OVERVIEW
In contrast, if you set the switch’s jumper to AS mode, the
RS-232
Fallback Switch
doesn’t give either the primary or alternate channel
higher priority than the other; it switches to whichever modem raises
the trigger signal first, and won’t switch back to the other modem
until the currently connected one drops the trigger signal.
Simple to set up and operate
Once the switch is configured, simply install it in a cool, dry
place close to the devices you want to attach to it and connect
the necessary cables. This simple procedure includes:
• Running cable from your primary modem (or other device)
to the rear-panel PRIMARY connector.
• Running cable from your alternate modem (or other device)
to the rear-panel ALTERNATE connector.
• Running cable from the master or common device (server,
PC, host, printer, etc.) to the rear-panel MASTER connector.
• Attaching the switch’s power cord.
The
RS-232 Fallback Switch
begins operating when it
receives power. The type of switching, whether it’s automatic or
manual, is determined by the position of the front-panel toggle
switch. LEDs light up to show whether it’s switched (automatically
or manually) to the primary device, or if it’s switched to the
alternate device.
NOTE: For all DCE connections to the the PRIMARY and ALTERNATE
connectors, use straight-through pinned RS-232 cable. For DTE
connections to the same ports, you’ll need specially cross-pinned cable
(for details, call Black Box Tech Support). For DTE connections to the
MASTER connector, use straight-through-pinned RS-232 cable. To attach
a DCE device to the MASTER port, use specially cross-pinned cable (for
details, call Black Box Tech Support).
Provides automatic modem backup if your leased line goes down.
Modem 3600 (MD1000A-
CABPAK-R2)
RS-232 Fallback
Switch
(SW901A)
Alarm System
RS-232 Cables
