• Increase font size
  • Default font size
  • Decrease font size

ASFOM Bus Transmission System

E-mail Print

ASFOM Bus Transmission System

ASFOM Bus Transmission System 1ASFOM Bus Transmission System 2ASFOM Bus Transmission System 3

The KBC ASFOM range allows optical bus systems to be configured simply and easily. Utilizing CWDM (Coarse Wavelength Division Multiplexer) technology, up to 16 optical wavelengths can be combined in a single fibre to create an add/drop bus arrangement. Each transmitter module must have a corresponding receiver module. In effect, the system is 16 individual point-to-point links integrated via the CWDM. As with all ASFOM products, the system provides a path for analog video, data, analog audio, contact closure, telephone and Ethernet signals. All signals are digitized providing excellent quality and guaranteed performance throughout the system. Video is offered with either 8 or 10 bit digital resolution without compression, providing real-time video images across the network.

Each wavelength provides an electrical bandwidth that can be filled with different signal types depending on the system requirement. The number and type of signal required to be combined at a location will dictate the number of wavelengths used. If return signals are required at the same location, another wavelength or wavelengths would be required to carry the signals. As an example, if the requirement is for 12 video signals, 2 duplex data signals, and a LAN connection at 4 locations, to be sent back to a control room, the design would be as follows: The 12 video signals with the forward data and Ethernet paths would take up 2 wavelengths and the return data and Ethernet would use a 3rd wavelength. In total, this system would use 12 wavelengths (3 from each of the 4 locations) and would therefore be configured on one fibre. Depending on system requirements, units are available in wall-mount, 1U or 2U 19” rack or 4U chassis card for integration within the FR4 chassis.

Typical System Configuration:

ASFOM Bus Transmission System schematic


  • Video, audio, data, telephone, contact closure, Ethernet, DVI, SDI & USB interfaces
  • Add-drop bus configuration
  • Application specific product configuration
  • All digital non-compressed
  • 8 and 10 bit video encoding
  • Multimode and singlemode
  • Wall-mount, rack or chassis configurations


Format: PAL / NTSC / SECAM
Input/Output: 1.0V pk-pk typical, 75Ω
Bandwidth: 5 Hz ~ 6.5 MHz
Digital Encoding (non compressed):       8 bit       10 bit
Differential Gain (10-90% APL):            <2%        <1%
Differential Phase (10-90% APL):          <2°         <0.7°
Signal to Noise Ratio (SNR) weighted:   >60dB      >67dB
Interface Standard: SMPTE 259M, 292M, 424M
Input/Output: 800mV pk-pk ±15%
Interface Standard: DVI 1.0
Video Display Resolution DVI: Up to 1920 x 1200 @ 60 Hz
HDTV: Up 1080p
Colour Depth: 24 bit
Pixel Clock: 165 MHz max.
Video Bandwidth: 3.96 Gbps
DDC Standard: DDC2/EDID 1.0/2.0
Data Formats: RS232, RS422, RS485 (2W & 4W)
Number of Two-way Channels: 1
RS-232 Data Rate: DC – 115.2 kbps
RS-422/485 Data Rate: DC – 250 kbps
Bit Error Rate: <1 x 10
Encoding Schemes: Manchester, Bi-Phase, NRZ, NRZI
Bandwidth: 10 Hz ~ 20 kHz
Audio Input/Output Levels: +/-9dBm, typical 0dBm
Input Impedance: 600Ω unbalanced or balanced
Output Impedance: 20kΩ unbalanced or balanced
Digital Encoding: 24 bits (AES-3)
Sampling Rate: 192 kHz
Signal to Noise Ratio: ≥80dB
Total Harmonic Distortion: ≤0.01%
Contact Closure
Response Time: 500μs
Input: Dry Contact Closure, TTL
Output: SPST Relay, Normally Open
Switch Rating: 1A @ 30 Vdc max, 0.5A @ 125 Vac max
Standard: IEEE 802.3 Compliant
Data Rate: 10 / 100 Mbps auto sensing

Voice Encoding: 8 bits PCM encoded
Operating: Mode Telco, PBX/telephone
Interface Standard: USB2.0 / USB1.1
Data Rate Low Speed: 1.5Mbps; Full Speed 12Mbps; High Speed 480Mbps
Port Power: 500mA max
Wavelength Single & WDM: 1310nm, 1550nm
Wavelength CWDM: 1310 ~ 1610nm
Fibre: Multimode, Singlemode
Number of Fibres: 1 or 2
Power Input Wall-mount: +12 Vdc
Power Supply for Wall-mount: Input: 100 ~ 240 Vac; Output: +12 Vdc
Rack Module: Input: 100 ~ 240 Vac @ 2A
Chassis Card: Supplied from FR4 PSU
Operating Temperature: -40°~ +70°C / -40°~ +158°F
Storage Temperature: -40°~ +70°C / -40°~ +158°F
Operating Humidity: 0 to 95% non-condensing
Mean Time Between Failure (MTBF): >100,000 Hours
Dimensions (Wall-mount L x W x H): 221mm x 155mm x 36mm (8.7” x 6.1” x 1.42”)
Dimensions (Rack) 1U: 19” 1U; 2U: 19” 2U
Number of 4U Chassis Card Slots: Depends on product configuration
Video: BNC 75Ω
DVI: DVI-I Female
Data: Screw Block Terminal
Audio: Screw Block Terminal
Contact Closure: 8 Way Screw Block Terminal
Telephone: RJ11
Ethernet: RJ45
USB Transmitter: 1 x Type B; Receiver: 4 x Type A
Fibre: ST or FC (ST fitted as standard)

Wall-mount: Screw Block Terminal
Rack: IEC