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Further information
Troubleshooting
If you experience problems when installing or using the ServSwitch Secure USB
unit, please check through this section for a possible solution. If your problem is
not listed here and you cannot resolve the issue, then please contact Technical
Support (details on the cover page and the final page).
No video from computer
• This is most likely to be associated with a mismatch between the host
computer’s video output and the DDC data held within the ServSwitch
Secure USB. Computers often need read the correct DDC data before they
will output a video signal. If digital DDC data is presented to a computer’s
analog video port, a video signal will not be generated. Conversely, if analog
DDC data is presented to a computer’s digital video port, a video signal will
also not be generated.
Depending on your DDC connection policy (see
for details), remember that the ServSwitch Secure USB will
only attempt to read the EDID information from your monitor when the
ServSwitch Secure USB is first powered on. To ensure that your monitor’s
EDID information is read and stored correctly, ensure that it is attached and
powered on when you switch on the ServSwitch Secure USB.
Video from some computers only
• Remember that the ServSwitch Secure USB does not convert digital video
signals to analog signals and vice versa so it is not generally possible to
mix digital and analog inputs. Mixed systems are possible in certain special
circumstances but these will require specialist assistance from Black Box
technical support.
SECT 5
Summary of threats and solutions
This section provides a list of potential security threats that the ServSwitch
Secure USB might face during operation and the special steps that have been
taken to counteract them.
Threat
Solution
Microprocessor
malfunction or
unanticipated software
bugs causing data to flow
between ports.
Unidirectional data flow is enforced by
hardware “data diodes” so data isolation
doesn’t rely on software integrity.
Subversive snooping
by means of detecting
electromagnetic radiation
emitted from the
equipment.
Carefully shielded metal case with dual
shielding in critical areas.
Detection of signals
on one computer by
monitoring for crosstalk
(leakage) signals on
another computer.
No connection to sensitive analogue inputs
(such as computer microphone ports) are
provided. A very high level of crosstalk
separation is provided between signals
from different computers.
Malicious modification of
microprocessor software
causing data to leak
between ports.
Data isolation is assured by hardware and so
is not compromised by any changes to the
microprocessor software. Microprocessors
use one time programmable memory so
flash upgrades are not possible. Case uses
counter-sunk screws which can be protected
by tamper-evident seals.
Buffered data within a
keyboard or mouse is sent
to the wrong computer
after switchover.
Keyboard and mouse are powered down
and reset between each switchover to
ensure that all buffers are cleared out.
Data leakage by means
of monitoring conducted
emissions on mains power.
The power circuitry provides strong
protection against signal leakage via the
power cable.
