
SC42DU-3 • SC42DHU-3 • SC21H-3
SECURE KVM COMBINER  
Ultra HD
SWITCHES
Interact with multiple computers presented on the same display at the same time 
using a single set of USB, audio, keyboard, video and mouse peripherals.
The KVM Combiner switch offered by HSL provides 
increased productivity in challenging multi-computer 
environments where users are required to view and 
interact with several computers at the same time. 
KVM COMBINER HIGHLIGHTS
• Secure by Design
HSL KVM Combiner switches are designed to meet with the security 
requirements demanded by government agencies, military, 
nancial institutions and similar security sensitive customers.
• Securely share peripherals across dierent security domains 
Securely share peripherals between computers that belong to 
dierent security classication levels while keeping the highest 
possible data separation security.
• Prevent information leaks
Obstacle threats derived from sharing and switching of 
vulnerable, untrusted or unauthorized peripheral devices. 
Block peripheral exploits, information leaks, eavesdropping, 
signal transmission, computer malware, hardware and rmware 
tampering by enforcing multilayered security mechanisms.
• View and control multiple computers simultaneously
Present and work with up to 4 computers at the same time.  
Cascade combiners to view and control up to 16 (4x4) computers 
on a single or dual displays.
• Filter USB Peripherals
Block unauthorized USB devices while allowing secure switching 
of smart card and biometric authentication devices between 
computers. Whitelist and blacklist specic USB devices based on 
VID/PID characteristics. 
Move mouse 
      to switch PCs
Speakers
PC #4
PC #3
Single        
Keyboard & Mouse
PC #2
PC #1
KVM COMBINER
KVM COMBINER
SECURE
SECURE
Multiple Sources
Optimize user experience while maintaining the highest 
isolation between computers and peripherals. 
Obviate the need for purchasing and installing 
dedicated, per-computer peripheral sets.
SECURITY FEATURES
•  USB Security
 - Block unauthorized USB devices.
 - USB authentication devices are authorize by default.
 - Whitelist and blacklist specic USB devices based on VID/PID 
characteristics. 
•  Video Security
 - Computer video input interfaces are isolated through the use of 
dierent electronic components, power and ground domains.
 - The display is isolated by a dedicated, read- only, EDID emulation 
for each computer. 
 - Access to the monitor’s Extended Display Identification Data 
(EDID) is blocked. 
 - Access to the Monitor Control Command Set (MCCS commands) 
is blocked. 
•  Keyboard & Mouse Security
 - The keyboard and mouse are isolated by a dedicated, USB 
device emulation for each computer. 
 - One-way, peripheral-to-computer data ow is enforced through 
unidirectional optical data diodes. 
 - Communication from computer-to-keyboard/mouse is blocked. 
 - Non HID (Human Interface Device) data transaction is blocked.
•  Audio Security
 - Enforce computer-to-speaker, one-way ow of sound through 
unidirectional optical data diodes. 
 - Prevent eavesdropping and line-in re-tasking by blocking 
speaker-to-computer communication.
•  Hardware Anti-Tampering
 - Any attempt to open the product enclosure will activate an antitamper system making the product inoperable.
 - Blinking LEDs provide a clear indication of a tampering event. 
 - Special holographic tampering evident labels on the product’s 
enclosure provide a clear visual indication if the product has 
been opened or compromised.
•  Firmware Anti-Tampering
 - There is no access to the product’s rmware or memory through 
any port.
 - Firmware is permanently stored on a non-reprogrammable 
Read Only Memory (ROM) to prevent any modication.
 - Firmware integrity is verified through a self-test procedure 
during power-up. Upon detection of a critical failure the device 
disables normal operation and provides the user with a clear 
visual indication of failure.
HSL4-Por t Secure Combiner KVM Switch 
System Diagram
© 2017 High Sec Labs Ltd. All rights reserved. All trade names are trademarks or registered trademarks of respective manufacturers listed. 
Specications are subjected to change without prior notice. Multiple patents pending. HDC12885 Rev 1.7
2-PORT

SPECIFICATION
PART NUMBER  SC42DU3 SC42DHU3 SC21H3
No. of Sources 4 4 2
CONSOLE PORTS
Displays
2 x DVI-I, single-link/
dual-link
2 x HDMI 1.4 1 x HDMI 1.4
Max Output Resolution
UHD 4K -  
3840X2160 @ 30 Hz  
(via DVI to HDMI cable)
DVI dual-link -  
2560X1600 @ 60 Hz  
(via DVI cable)
Supporting UHD 4K 
resolutions up to
3840x2160
Supporting UHD 4K 
resolutions up to
3840x2160
Mouse and Keyboard
USB Type A, PS/2 USB Type A, PS/2 USB Type A
Audio Jack  3.5 mm Jack 3.5 mm Jack 3.5 mm Jack
fUSB Port USB Type A USB Type A N/A
COMPUTER PORTS
Display Type
1 x DVI-I, single-link/
dual-link
1 x DVI-I, single-link/
dual-link
1 x HDMI 1.4
Max Input Resolution 1920 x 1200 1920 x 1200 1920 x 1200
Mouse and Keyboard
USB Type B USB Type B USB Type B
Audio Jack  3.5 mm Jack 3.5 mm Jack 3.5 mm Jack
fUSB Ports USB Type B USB Type B N/A
PHYSICAL
Dimensions 342 x 148 x 42 mm / 13.4 x 5.8 x 1.6 inches
177 x 82 x 35 mm /  
6.9 x 3.2 x 1.3 inches
Weight 1.61 kg (3.5 lbs) 0.52 kg (1.1 lbs)
POWER
Power Requirements 35W Max 12V DC, 1.5A
AC Input 100 to 240V AC 100 to 240V AC
Power Type Internal External
ENVIRONMENTAL
Operating Temperature 32° to 104° F (0° to 40° C)
Storage Temperature -4° to 140° F (-20° to 60° C)
Humidity  0-80% RH, non-condensing
SOFTWARE
Supported OS Windows, Linux, Mac
CERTIFICATION
Product Certication CE, RCM, FCC class B, VCCI, TUV US, TUV Canada
GENERAL INFO
Made In ISRAEL
Product life-cycle 10 years 
Warranty 2 Years
SC42DU-3
SC42DU-3 • SC42DHU-3 • SC21H-3
SC42DHU-3
SC 21H-3
OPERATIONAL HIGHLIGHTS
• Freeze USB (SC42DU-3, SC42DHU-3)
Assign the USB port to a specic computer 
while switching the keyboard, video, mouse 
and audio between other computers. Useful 
for various scenarios, for instance, when a 
USB smart card reader must remain mapped 
to a certain computer.
• Smoothly switch between computers 
(Virtual Display Technology)
Automatically switch control from one 
computer to another by dragging the mouse 
cursor over the computer’s display border. 
Peripherals switch to the next computer 
without having to press any buttons once 
the mouse is passing the display border. 
• View applications in Ultra High 
Denition (UHD) 4K video quality
Never compromise on video quality. Run 
graphic-intensive, ultrahigh definition 
applications on all single and dual monitor 
KVM models.
• Avoid typing mistakes
Since two-way communication is blocked by 
the KVM security, keyboard lock LEDs do not 
function. Help users avoid typing mistakes 
by visually indicating the status of keyboard 
locks (CAPS-LOCK | NUM LOCK | SCROLL 
LOCK) on the product’s front facing panel. 
• Native touch screen support
Interact with all the computers that are 
connected to the KVM Combiner using 
touch screen gestures. No need to install 
any driver or software. 
• Flexible screen layout
Resize source scaling and aspect ratio 
to create Tile, Scale and Custom display 
layouts that t user needs. Support screen 
duplication & extended screen view modes.
© 2017 High Sec Labs Ltd. All rights reserved. All trade names are trademarks or registered trademarks of respective manufacturers listed. 
Specications are subjected to change without prior notice. Multiple patents pending. HDC12885 Rev 1.7