Welcome to Kramer Electronics (since 1981): a world of unique, creative and
affordable solutions to the infinite range of problems that confront the video,
audio and presentation professional on a daily basis. In recent years, we have
redesigned and upgraded most of our line, making the best even better! Our
500-plus different models now appear in 8 Groups1, which are clearly defined
by function.
Congratulations on purchasing your Kramer Cobra R500A Video-Audio receiver and/or Cobra R500-2 Video-RS-232 receiver. The Kramer Cobra
Series System extends VGA and audio signals over ordinary Category 5
cable. This manual covers the Cobra R500A Video-Audio receiver with
audio, and the Cobra R500-2 Video-RS-232 receiver with RS-232 serial
support. For information on the respective transmitter unit, refer to the
appropriate manual included with the transmitter.
The package includes the Cobra R500A Video-Audio receiver or the Cobra R500-2 Video-RS-232 receiver, an external power supply, and this user
manual2.
The Kramer Cobra series products are not compatible with Kramer non-Cobra
series products.
2 Getting Started
We recommend that you:
Unpack the equipment carefully and save the original box and packaging
materials for possible future shipment
Review the contents of this user manual
Use Kramer high performance high resolution cables3. You may
also need CAT 5 cable. We recommend that you use our Kramer Pico
Skew CAT 5e cable4
1 GROUP 1: Distribution Amplifiers; GROUP 2: Video and Audio Switchers, Matrix Switchers and Controllers; GROUP 3:
Video, Audio, VGA/XGA Processors; GROUP 4: Interfaces and Sync Processors; GROUP 5: Twisted Pair Interfaces;
GROUP 6: Accessories and Rack Adapters; GROUP 7: Scan Converters and Scalers; and GROUP 8: Cables and Connectors
2 Download up-to-date Kramer user manuals from the Internet at this URL: http://www.kramerelectronics.com
3 The complete list of Kramer cables is on our Web site at http://www.kramerelectronics.com
4 In addition, you may also need 1/8” (3.5mm) audio cable with RCA jac ks, 1/8” (3.5mm) serial cable with DB9 connector,
and Video cable with HD15 connectors
1
Overview
3 Overview
CAT 5/5e/6 cabling for this product must be pinned to the TIA-EIA T568B
wiring specification (see appendix A). We also highly recommend that all
CAT 5 cables be pre-terminated and tested. Cables terminated on-site or in an
existing infrastructure should be tested before use to ensure compliance with
the TIA-EIA T568B specification. Using incorrectly terminated CAT 5 cables
can damage this product.
We recommend using our Kramer Cobra ultra low skew cable—BC-HDTP
(solid bulk) or BCP-HDTP (solid plenum bulk)—available in lengths of 700'
(210m) and 1300' (390m).
Our Kramer Cobra series products are compatible with CAT 5/5e/6 data
cabling as well as skew free CAT 5/5e cabling manufactured for video
applications. Note that some skew free CAT 5 is specific to a particular
vendor and is not compatible with our products. Ensure any skew free CAT 5
cable is non-proprietary prior to purchase / installation. CAT6 cable, due to
the manufacture method, can exhibit much greater skew than standard CAT
5/5e and may require skew compensation beyond what the standard product
offers. Contact Kramer Electronics for assistance.
Achieving the best performance means:
Connecting only good quality connection cables, thus avoiding
interference, deterioration in signal quality due to poor matching, and
elevated noise levels (often associated with low quality cables)
Avoiding interference from neighboring electrical appliances that may
adversely influence signal quality and positioning your Cobra R500A / R500-2 in a location free from moisture and away from excessive sunlight
and dust
Caution – No operator-serviceable parts inside unit.
Warning – Use only the Kramer Electronics input power
wall adapter that is provided with this unit1.
Warning – Disconnect power and unplug unit from wall
before installing or removing device or servicing unit.
Warning –This equipment is not intended for, nor does it
support, distribution through an Ethernet network. Do not
connect these devices to any sort of networking or
telecommunications equipment!
1 For example: model number AD2512C, part number 2535-000251
2
KRAMER: SIMPLE CREATIVE TECHNOLOGY
Setup and Installation
4 Setup and Installation
First ensure all units have been configured for correct operation and signal
types. See appropriate configuration sections of this manual and the respective
transmitter manual.
4.1 Making the Connections
This section contains figures showing connections with the specific Cobra
R500A / R500-2 series models. In general, however, the connection and setup
procedure at both transmitter and receiver ends is as follows:
At the transmitter end (refer to the transmitter user guide):
1. Connect the source video to the Cobra Series transmitter video input port,
which is an HD15 connector labeled SOURCE IN.
2. If desired, attach a local monitor via the local monitor port to LOCAL
OUT.
3. Make your audio/serial connections via the 1/8” (3.5mm) audio connector
or DB9 serial connector (transmitter model dependent).
4. Connect the CAT 5 cable to the transmitter.
5. Apply power on the transmitter. The LED should light and, if there is a local
monitor attached, a video image should appear on the monitor’s screen.
At the receiver end:
1. Connect the VIDEO OUT HD15 connector to the display unit and attach
any audio cabling.
2. Connect a 1/8” (3.5mm) audio or serial cable to the AUDIO or SERIAL
OUT connection (model dependent).
3. Connect the CAT 5 cable to the UTP INPUT connection.
4. Apply power. The LED should light and video should appear on the
display(make sure display is powered ON).
5. Adjust video levels.
With regard to connecting the cables:
We recommend mounting and connecting all cabling to the Cobra R500A
/ R500-2 components before applying power.
Be sure that the CAT 5 cable you intend to use has been tested to comply
with the T568B wiring specification (see Appendix A).
3
Setup and Installation
4.2 Connections on the VGA/Audio Transmitter
The single-port units with audio support video and audio signals over CAT 5
cable. The audio signal is line-level audio, and powered speakers are
required. Figure 1 shows the Kramer Cobra transmitter with Audio
Transmitter connections, and Figure 2 shows the Kramer Cobra R500A
The single-port units with audio support video and serial signals over CAT 5
cable. The serial signal is 3 wire TX, RX, GND serial. Figure 3 shows the
Kramer Cobra transmitter with serial Transmitter connections, and Figure 4
shows the Cobra R500-2 Video-RS-232 receiver. See Appendix A for cable
pinouts of the Cobra R500-2.
Figure 3: Transmitter Connections
(Note: Both serial connection types are shown, but only one is used
depending on the model and settings).
The Cobra R500A and the Cobra R500-2 are configurable for various video,
audio and serial modes. Note that a compatible transmitter unit must be used
at the source end. Reference the appropriate transmitter user guide or call for
technical assistance. It is not possible to change an audio unit to a serial unit
and vice versa. A dipswitch on the receiver unit is used to set the video,
audio, serial configuration mode. Table 3-1 below shows the configuration
settings (ON = down, OFF = up):
NOTE: There are no user serviceable parts inside the Cobra R500A / Cobra
The only adjustments required on the Cobra R500A and Cobra R500-2 are the
SW positions 4 and 5 which must be set to compensate for cable length.
Using the table below as a guide, turn SW positions ON or OFF for best
picture clarity (ON = down, OFF = up):
Table 2: Cable Length EQ Settings
Cable distance EQ settings
Cable Length 4 5
(0-125 Ft)
(125-250 Ft)
(250-375 Ft)
(375-500 Ft)
6
OFF OFF
ON OFF
OFF ON
ON ON
KRAMER: SIMPLE CREATIVE TECHNOLOGY
Solutions to Common Problems
5 Solutions to Common Problems
In most cases, nearly every issue with the Cobra series can be resolved by
checking the CAT 5 termination and making sure that it’s pinned to the
TIA/EIA 568B wiring specification. However, there may be other problems
that cause the system to not perform as it is designed. Below are solutions to
the most common installation errors.
Problem:
Solution:
Problem:
Solution:
Problem:
Solution:
Problem:
Solution:
Problem:
Solution:
No video signal at the transmitter local port or at the receiver.
Check that both units are powered.
Ensure EQ adjustment switches are set correctly
Make sure the CAT 5 cable is terminated correctly per the
TIA/EIA 568B wiring specification.
Is the display device powered on and functioning?
Check to ensure display settings (resolution, refresh rate, and so
on) are compatible with input signal.
Poor video quality.
Have all receiver adjustments been finished?
Ensure EQ adjustment switches are set correctly
Check all cable connections
The video signal’s refresh rate may be set too high. Reset to a
lower refresh rate in your monitor-configuration menu
Poor audio quality. (Cobra R500A only)
Powered speakers are required. Make sure speaker power is ON
Check input source levels from the source device. Make sure the
audio source is not overdriven or underdriven.
Audio is summed left and right for “A” versions. If using a single
channel, both audio inputs must be connected at the transmitter
end for full audio gain. Audio is line level
Low Level Audio may require the 100 termination disabled.
Turn SW1 off to disable termination
Serial communication doesn’t work correctly. (Cobra R500-2 only)
Are the serial devices connected properly? Are the serial
parameters correct for source/destination devices?
Are the serial cables terminated correctly? If a null-modem cable
is used, it must be placed at the receiver end.
When using RS-232 transmitters or receivers in daisy chains, CAT
5 switches, or CAT 5 distribution amps, the serial signal is a
unidirectionally broadcast mode only. In this mode, all other
Cobra CAT5 Video System devices must be the simplex serial
type. Cobra R500-2 use 3 wire (TX,RX,GND) signals only via the
1/8” connector (see Appendix A for pinout)
“Green shift” or “green washout” on multimedia signals
The standard video model is designed to function with DC
coupled signals in which the black level is referenced to 0 volts.
For five-component (RGB/H&V) AC coupled video, the Cobra
transmitter has been designed with full DC restoration capability.
Refer to the transmitter user manual.
Note: The stereo audio input at the transmitter is summed and output as mono
audio on both channels at the receiver.
9
Technical Specifications
6 Technical Specifications
Table 6: Technical Specifications1 of the Cobra R500A, Cobra R500-2
CABLE REQUIRED: Category 5, 5e, 6 shielded or unshielded twisted pair
COMPLIANCE: CE; FCC Class A, IC Class/class A
VIDEO SUPPORT: To UXGA (1600x1200 @ 60Hz), RGBHV, RGB, Composite, s-Video,