Kramer Electronics VP-61xl User Manual
Kramer Electronics, Ltd.
USER MANUAL
VGA/XGA/Audio Switchers
Models:
VP-61N
VP-61xl
IMPORTANT
KRAMER ELECTRONICS LTD.
: Before proceeding, please read paragraph entitled
"Unpacking and Contents"
Table Of Contents
Section Name Page
1 INTRODUCTION 2
1.1 A Word on VGA/XGA/Audio Switchers 2
1.2 Handling Graphics Signals 2
1.3 Factors Affecting Quality of Results
2 HOW DO I GET STARTED 5
3 UNPACKING AND CONTENTS 5
3.1 Optional Accessories 5
4 VGA/XGA/AUDIO SWITCHER 6
4.1 Getting to know your VP-61xl Switcher 7
5 INSTALLATION 8
5.1 Rack Mounting 8
6 CONNECTING TO VGA/XGA/DEVICES 8
7 CONNECTING TO AUDIO DEVICES 8
8 USING THE SWITCHER 8
8.1 Powering UP the Switcher 8
8.2 Selecting an Input on the Switcher 8
8.3 Controlling the VP-61xl 9
8.3.1 DIP Switches 9
8.3.2 The "Reply" option 9
9 CONNECTING TO A PC 10
9.1 PC Control Software 11
10 SPECIFICATIONS 11
11 TROUBLESHOOTING 11
11.1 Power and Indicators 12
11.2 VGA/XGA Signal 12
11.3 Audio Signal 12
Limited Warranty
13
List Of Illustrations
Figure Description Page
1 VP-61xl Front/Rear Panel Features 7
2 RS-232 Control Connector Wiring 10
3 Connecting Multi-Machines 10
List Of Tables
Table Description Page
1 VP-61xl Front/Rear Panel Features 7
2 DIP Switch settings 9
4
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1 INTRODUCTION
Congratulations on your purchase of this Kramer switcher. Since 1981, Kramer
has been dedicated to the development and manufacture of high quality
video/audio equipment. The Kramer line has become an integral part of many of
the best production and presentation facilities around the world. In recent years,
Kramer has redesigned and upgraded most of the line, making the best even
better. Kramer’s line of professional video/audio electronics is one of the most
versatile and complete available, and is a true leader in terms of quality,
workmanship, price/performance ratio and innovation. In addition to the Kramer
line of high quality switcher, such as the one you have just purchased, Kramer
also offers a full line of high quality distribution amplifiers, processors,
interfaces, controllers and computer-related products. This manual includes
configuration, operation and option information for the VP-61xl
VGA/XGA/Audio switcher. The VP-61N is identical to the VP-61xl but it does
not include the audio channels.
1.1 A Word on VGA/XGA/Audio Switchers
VGA/XGA/Audio Switchers route signals to one or more selected users. They
vary in the number of inputs, looping capability, programming capability, number
of outputs, operating format, bandwidth and input/output coupling.
VGA/XGA/Audio Switchers are used to select which source is to be switched to
which acceptor for recording or monitoring, with no discernible signal
degradation. A good quality VGA/XGA/Audio Switcher amplifies the incoming
signal, pre-compensates the signal for potential losses (resulting from the use of
long cables, noisy source, etc.) and routes the signal(s) to buffered and amplified
outputs. Often, a signal processor is inserted between the source and the
VGA/XGA/Audio switcher for correction and fine-tuning of the source signal
before routing. The front panel of this Kramer switcher is designed to be simple
to operate. The machine described in this manual switches one of several PC's to
a monitor. It is RS232 controlled for remote PC operation. It excels in high source
isolation for minimal crosstalk and very large bandwidth.
1.2 Handling Graphics Signals
A computer generated graphics signal is usually comprised of 5 signals: Red,
Green, Blue -which are analog level signals and two TTL (logic) level signals Horizontal Sync and Vertical Sync. (Digital graphics cards and monitors use a
different signal format, and will not be discussed here, as they are not relevant.)
Computer graphics resolution is measured in pixels and signal bandwidth. The
more pixels (picture elements) on the screen, the more detailed the image. VGA,
S-VGA, XGA, S-XGA and U-XGA are terms describing the graphics resolution
and the color depth. Color depth represents the maximum number of
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simultaneously displayed colors on the screen and is measured in bits. 24 and 3236 bits of color depth represent millions to billions of color shades available on
the screen at any given moment. (It should be born in mind, though, that the
human eye can resolve only a few thousands colors!) The more detailed the
image (higher resolution) and the higher the color depth the more real the image
will look. The highest resolution of standard VGA was 640x480 pixels with 4 bits
of color (16 colors). The standard VGA was able to use more colors (256) but at a
lower resolution, around 320x200 pixels, which was very crude. Common
resolutions used nowadays for computer graphics vary from 1024x768 up to
2000x1600 pixels with “high color” - 16 bits of color, representing 64,000
different colors, up to “true color” - 24 bits or more, representing from 16.7
million colors up to several billion. Displaying such a detailed and colorful image
on the screen needs enormous graphics memory per frame, as well as very high
speeds for “writing” so many pixels on the screen in real time. The amplifiers that
carry those signals must be able to handle those speeds and hence signal
bandwidth.
The standard VGA at 640x480 resolution needed amplifiers with 20-30MHz
bandwidth. At 1600x1200 or even at 1280x1024 (S-XGA), those amplifiers will
fail completely. In order to faithfully amplify and transmit modern highresolution graphics, amplifiers with bandwidths of 300 MHz and more are
needed. Those amplifiers, besides the enormous bandwidth they handle, need to
be linear, to have very low distortion and be stable. Stability of an amplifier is its
ability to avoid bursting into uncontrolled oscillation, which is in adverse
relationship to the speed it can handle. The tendency to oscillate is further
enhanced by the load impedance. The load impedance of a system is usually not
just a resistor. A cable connected to an amplifier (leading to the receiver or
monitor) may present a capacitive and/or an inductive load to the amplifier. This
is the main cause of instability. The quality problems of a load or cable may
severely degrade the bandwidth, linearity, and stability of the amplifier and in
general its ability to faithfully reproduce the signal.
Cables affect image resolution. Longer cables, due to imperfect characteristics,
cause high frequency deterioration and hence image “smear” and loss of
resolution. In computer graphics especially, this adverse effect is very much
accentuated. The amplifiers should therefore cope with an additional task compensating for cable losses up to the maximum useful operation distance.
High-resolution graphics systems should use very high quality cables for image
transmission. The cables should be shielded to eliminate externally induced
interference but the shield might itself increase the capacitance of the cable, and
therefore, cause deterioration in the image’s resolution and clarity. Standard
quality cables can only be a few meters long. For longer distances, the compound
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cable is replaced by five individual coax cables, which are bulky and
cumbersome for use. Even then, the distance is limited to several tens of meters.
The imperfect behavior of a cable may create other problems resulting from its
failure to accurately match the system’s required impedance. The result of this,
especially at high frequencies, is “shadows” or “ghosts” on the image, resulting
from standing waves and electronic reflections running back and forth between
transmitter and receiver. Another aspect to consider is the sync. As sync signals
are logic signals, which are not treated as analog signals, the receiver does not
terminate the line, and therefore the line is not matched. A host of problems can
occur when sync signals are sent over long, unterminated, unmatched cables. The
result might be image breakdown or distortion due to improper sync information.
The amplifier that drives the analog section of the graphics data should also be
able to buffer, recover and send the sync information in such a way that it is
received properly at the receiving end.
1.3 Factors Affecting Quality of Results
There are many factors affecting the quality of results when signals are
transmitted from a source to an acceptor:
Connection cables - Low quality cables are susceptible to interference;
they degrade signal quality due to poor matching and cause elevated noise
levels. They should be of the best quality.
Sockets and connectors of the sources and acceptors - So often
ignored, they should be of highest quality, since "Zero Ohm" connection
resistance is the target. Sockets and connectors must also match the
required impedance (75ohm in video). Cheap, low quality connectors tend
to rust, thus causing breaks in the signal path.
Amplifying circuitry - Must provide quality performance when the
desired end result is high linearity, low distortion and low noise operation.
Distance between sources and acceptors - Plays a major role in the final
result. For long distances of over 15 meters (~2 to 3 meters for
VGA/XGA) between sources and acceptors, special measures should be
taken in order to avoid cable losses. These include using higher quality
cables or adding line amplifiers.
Interference from neighboring electrical appliances - They can have
an adverse effect on signal quality. Balanced audio lines are less prone to
interference, but unbalanced audio should be installed far from any mains
power cables, electric motors, transmitters, etc. even when the cables are
shielded.
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