Bi Directional SD HD 3G 12G SDI+ Analog Audio + RS232, 485, 422 Data + Tally Fiber Optic Transceivers

Cobra II
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Description Features Drawings Model Selection Specification Q&A Documents Support

Cobra II TX/RX is a revolutionary 12G-SDI UHD multi-function fiber optic transmitter and receiver sets are now combining multiple effective inputs and outputs to meet client demand in the market. Through a single optical fiber, these units can transmit one channel of bidirectional 12G-SDI video, bidirectional 3.5 stereo audio, and bidirectional RS232/485/422 serial port data/bidirectional tally signal with CWDM technology. All of this is achieved with zero delay and no compression, ensuring high-quality signal extension up to 10km.

Each unit has also SDI loop ouput for local siganl monitoring


These are easy-to-use plug-and-play devices. The set includes the transmitter, receiver, and both power supplies. LC/PC connectors are standard. They are effective in both hot and cold weather and are, of course, resistant to electromagnetic interference




  1. One-channel bidirectional SD, HD, 3G, 12G-SDI video transmission; the transmitter has video loop-out and HD audio and video

  2. CWDM optical multiplexing allows ultra-low delay - 1ms

  3. SDI Video formats supported: ST-2082-1 (12G), ST-2081-1 (6G), ST-424 (3G), ST-292 (HD), and ST-259 (SD); compatible with DVB-ASI and AES10 (MADI).

  4. upports up to 16 embedded SDI audios

  5. Both the transmitter and receiver feature reclock functionality.

  6. The signal input includes an automatic cable equalization (EQ) function, and the output features drive (CD) functionality.

  7. One-channel bidirectional 3.5 stereo audio transmission Independent

  8. Transparent transmission of RS232/485/422 serial port data.

  9. One-channel bidirectional tally signal.

  10. Single-mode Fiber with a 10km transmission distance.

  11. One Simlex LC Optical connector

  12. Plug-and-play operation, no debugging required; power supplies are included.


Model Selection

COBRA II TX/RX - Contains 2 units - Transmitter (Side A) and Receiver (Side B).  -10Km version over one single mode fiber

COBRA II TX is a Fiber Optic (Side A) transceiver with 12G SDI IN with Loop, 12G SDI Out, Audio In, Audio Out, RS232, RS485, RS422 IN/OUT, and Tally IN/OUT.

COBRA  II RX is a Fiber Optic (Side B) transceiver with 12G SDI IN with Loop, 12G SDI Out, Audio In, Audio Out, RS232, RS485, RS422 IN/OUT, and Tally IN/OUT


Fiber parameters



Fiber type

9/125um single-mode

Transmitter power


Receiver sensitivity


Fiber connector


Optical module parameter

Single fiber single mode 10km

Video parameters

Protocol standard


SMPTE rate

270Mbit/s,1.48Gbit/s,2.97Gbit/s,5.94Gbit/s, 11.88Gbit/s


SMPIE 259M       SD-SDI     480i,576i

SMPIE 344M       ED-SDI     480P, 576P

SMPIE 292M       HD-SDI     720P, 1080i

SMPIE 424M       3G-SDI     1080P60Hz

SMPIE ST-2081    6G-SDI     2160P30Hz

SMPIE ST-2082    12G-SDI    2160P60Hz

EQ mode 

11.88Gbps at 75m

5.94Gbps at 120m

2.97Gbps at 200m

1.485Gbps at 300m

270Mbps at 600m

Signal amplitude





The BNC meets the IEC169-8 standard

Audio parameters

Sampling frequency


Sampling depth


Dynamic bandwidth


Total harmonic distortion (THD)


Signal to noise ratio (SNR)


Audio input/output impedance


Signal level

VPP 3.5V

Physical interface

3.5mm stereo audio socket

Signal type

Stereo Audio

Data parameters


EIA RS-232,RS-485,RS-422 standard

Physical interface

Industrial terminal/3.81mm

Baud rate

50bps to 115200 kbps (support non-standard baud rates)


3-wire(RXD,TXD,GND), full-duplex, point to point communication


2-wire (A, B), half-duplex, point to multi-master-slave communication


4-wire, full-duplex

RS485 circuit parameters

RS-485 pull-up resistance/pull-down resistance

4.7 kΩ,4.7 kΩ

RS-485 terminal resistance

N/A,120 Ω and 120 kΩ

Tally signal parameters

Level type


Input level range


Output level parameter

0V or 3.3V

Default state

No-voltage output (0V)

Physical interface

Industrial terminal / 3.81mm

Mechanical parameters

The shell metal

Aluminum alloy

Product size

116*128*30mm  / 4.57"x 5.04" x 1.18 inches

Installation method

Desktop type


Working temperature

-20°C ~+75°C

Storage temperature

-40°C ~+85°C

Relative humidity

5 to 95% (non-condensing)


> 10,0000 hours


Question and Answers

A tally light, also known as a tally indicator or tally lamp, is a visual signal used in broadcasting and video production to inform on-air talent, camera operators, and others involved in the production about the status of a video camera. Tally lights serve as a communication tool to coordinate the timing of when a camera is live or on-air.

Here's how tally lights typically work:

  1. Live Status: When a particular video camera is selected to be live or "on the air," a tally light associated with that camera illuminates. This signals to the on-air talent that they are currently being recorded or broadcast.

  2. Off-Air Status: Conversely, when a camera is not live or off-air, the tally light associated with it remains off or changes to a different color, indicating to the talent that they are not currently being recorded.

  3. Coordinated Communication: Tally lights are typically connected to a central control system, such as a video switcher or production switcher. The director or switcher operator controls which cameras are live, and the tally system ensures that the appropriate tally lights are illuminated accordingly.

Tally lights are crucial for live television broadcasts, as they help talent and camera operators know when they are on-air or off-air, allowing for smoother transitions and more effective communication during a broadcast. They come in various forms, such as small LED lights mounted on cameras or larger indicator lights in a studio environment, and may use different colors or patterns to indicate status.

We will be happy to help you with optical multiplexing, we are experts in that field.
Could you please tell us what you currently transport using your 96 fibers?
 Is it Gigabit Ethernet on each fiber or SDI video? 
Do you have any documentation or drawings so we can determine how and what we can do? 
Also, what is the optical distance from the beginning to the end? 
Is it a straight fiber or are there multiple hubs? 
Do you have any optical loss measurements? 
User's Manual is avalible only for logged users.
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