Developer's Blog

Video CAT Pro

2011-08-19T20:21:00.006+02:00

Video CAT Pro

Longer cable distance, easier installation, prefect picture.

We designed Video CAT Pro (also know as BFR Digital's 1 mile box) to facilitate the transmission of video over a copper cable length of 1800m.

Differential video signals sent over long distances of twisted pair wire exhibit large high frequency attenuation, resulting in loss of high frequency detail/blurring. The exact loss characteristic is a complex function of wire gauge, length, composition, and coupling to adjacent conductors.

The video signal can be restored by applying a filter with the exact inverse transfer function to the far end signal. Video CAT Pro is designed to compensate for the losses due to long cables, and incorporates the functionality and flexibility to match a wide variety of cable types and loss characteristics.

Video CAT Pro has been designed to be fully automated with the only manual function being the selector between CAT5 and RG59.

The VCP-ISL-01R offers 99% video reproduction at 1000m (same as a camera connected to a monitor on a 1m lead) and 75% video reproduction at 1800m (same as a camera connected to a monitor on 250m of RG59).

Application

http://www.bfrdigital.co.za/videocatpro_1.htm

I-WIE Wiegand Interface Isolators

2011-08-19T19:49:00.007+02:00

We are excited to introduce our new range of Wiegand isolator range of product. All data lines are optically isolated.

I-WIE5 - Wiegand isolator for D0, D1, LED1, LED2 and 12Vdc at 10Watt

I-WIE4 - Wiegand isolator for D0, D1, LED1 and LED2

I-WIE2 - Wiegand isolator for D0 and D1

Midspan PoE PSE (Power Sourcing Equipment) with Surge Protection

2011-05-14T20:22:00.006+02:00

BFR Digital is proud to introduce high-end, high-power solutions for PoE (Power over Ethernet) IP cameras and other devices. All our products feature a self-contained power supply and surge protection. Our production range will cater for the most demanding industrial IP CCTV applications.

As we all know, PoE offers the advantage of power and data for a network device on one cable.

Our products are 10/100 IEEE 802.3af complaint PoE Midspan PSE featuring:

· Wide input supply voltage range

· Self contained 48v power supply

· Built-in surge protection

· High power output

· Intelligent PoE status indication and power management

· 1.5KW zone 2 protection level

Products in the range:

· 10 port PSE rack mount unit with a total user power rating of 75W or 7.5W per port

· 4 port PSE stand alone unit with a total user power rating of 75W or 15W per port

· 2 port PSE stand alone unit with a total user power rating of 25W or 12.5W per port

· Single port PoE stand alone camera end protection device only

CCTV Infrastructure

2011-04-21T22:45:00.001+02:00

Cable quality versus CCTV image quality

Graham is the project manager for a CCTV systems integration company in Johannesburg. While trying to commission a CCTV system Graham just couldn’t get the cameras into focus. The cameras were all focused on a test monitor at the camera and they all appeared to be in-focus, yet at the recorder the cameras were all out-of-focus. The more puzzling question Graham had was, why were the Pan-Tilt-Zoom (PTZ) cameras out of focus? The PTZ cameras all had auto-focus lenses and no matter what the PTZ cameras were looking at they looked out-of-focus.

Graham was at his wits’ end. He had replaced the PTZ cameras, then he replaced the Digital Video Recorder (DVR) along with the monitor and still the camera images were out-of-focus.

Graham then decided to bench test the equipment. He removed the PTZ cameras, a few static cameras, the DVR and the monitor and plugged the systems together at his office on short fly-leads. Surprise, surprise, all the components worked and Graham had a fully operational system. The cameras, the DVR and the monitor were not at fault.

After much testing and investigating we found that Graham had two “challenges” with this installation:

1. Graham had used poor quality video baluns

2. Graham had installed poor quality cable

The solution to the above challenges was resolved by doing the following:

1. The video baluns were replaced with BFR Digital’s Video CAT products and the video image improved but was still out-of-focus.

2. It was only after the installation was re-cabled that the problem was successfully resolved.

What Graham learnt from this experience can be summed up in one sentence. Even if you use high quality equipment such as BFR Digital’s Video CAT with a leading brand camera and DVR, connecting these components with a poor quality cable will always result in a poor quality video image.

Do IP CCTV systems fail to deliver when poor quality CAT5 or CAT6 is used?

Absolutely! The digital high-speed data stream will experience signal attenuation and crosstalk just like an analogue video signal did on poor quality cable. This always results in reduced data throughput on that particular cable.

Remember, using good quality components installed correctly will produce superb video images every time.

CCTV Infrastructure

2011-04-21T22:40:00.002+02:00

The CCTV components that nobody ever thinks about but could substantially reduce the costs of installing a CCTV system

Uday is the owner of a CCTV systems integration company in Tanzania. During the height of the recession in 2009 Uday kept losing CCTV deals to a South African company. The burning question for Uday was how could these South African’s under quote him? He was the local and after all the South African’s incurred extra costs like flights and accommodation. How could they under quote him when he didn't have these extra overheads? Also, the South African’s were quoting on the same camera and digital video recorder (DVR) that he was quoting. So the answer wasn’t that the South African’s were quoting inferior products.

Uday found the answer after many months and the loss of many deals. As these systems aged and required camera maintenance, like cleaning and refocusing, the customers began call Uday. It just wasn't feasible for the South Africans to do maintenance on these CCTV systems in Tanzania.

It was on Uday's first maintenance call that he made some startling discoveries. Uday took the opportunity and accompanied his maintenance crew to the customer. Uday was expecting inferior workmanship and product but this was not the case. The product installed was as per the customers specification, the same specification he had quote. To Uday’s astonishment the installation was neatly done and to a high standard.

What perplexed Uday was the lack of power supplies, RG59 coax cable and camera power cable. Instead Uday found a 16-channel box (VC-016PR) next to the DVR. The outputs of the VC-016PR were 16 RG59 coax cables connected to the DVR; the inputs were 16 CAT5 cables. At the camera Uday found a little silver box (VC-01PM) that the CAT5 cable from the control room plugged into and on the other side there was a 12volt DC power connector and a BNC connector for the camera.

Uday had discovered what was to him a unique installation methodology. He was astounded at how a camera’s video signal and power requirements could be managed on one CAT5 cable to a maximum cable length of 300 meters.

You see Uday pays $1 US per meter of RG59 and $1 US per meter of power cable but the price of CAT5 is only $0.8 US per meter. Uday worked out that by using a VC-016PR at the DVR and one VC-01PM per camera, his CCTV infrastructure, i.e. cabling, conduiting and trunking, costs would be reduced by 20%. Uday realized another benefit after using these products for the first time, because he was using less cable and conduiting his labour costs had also reduced. His installation team finished the installation faster than he had expected allowing for a further cost reduction of 5% on labour.

Uday is now a regular BFR Digital customer. Not only has Uday benefitted from our technology but he has also introduced Amar from Kenya and Faisal from the Middle East to BFR Digital's Power CAT products.

Uday is not the only one to understand the benefit of BFR Digital's Power CAT products. We understand that Uday’s position is unique and that the cost of doing business in Central Africa is high but many local end-users like Standard Bank have specified our Power CAT range of products and reduced the overall costs of their CCTV systems.

The Future of Analogue CCTV in South Africa

2011-02-10T20:53:00.002+02:00

Although IP CCTV system sales have increased and in some first world countries have overtaken Analogue CCTV system sales. In South Africa and other third world countries Analogue CCTV systems still dominate the market.

It is reasonable to think that in a few years one will only find an analogue CCTV camera as part of a museum display along with vidicon and ultracon cameras. Especially with IP creating an extraordinary amount of hype in the CCTV market. With all this hype you would think that IP sales are rocketing but this is not the case.

Analog Devices say, “Analogue is everywhere”. Although an IP camera produces a digital output, once this signal leaves the camera it enters the analogue world. This digital signal is still influenced by surges, induction and cable attention, which limits the cable distance to 95 meters between devices. This is a challenge for System Integrators that are accustomed to transmitting analogue CCTV video signals up 1000 meters on copper cable. Not only is the IP CCTV camera equipment more expensive but the infrastructure required for an IP CCTV system is also substantially more expensive as a fibre optic cable infrastructure is required to guarantee throughput on cable distances greater than 95 meters.

Major silicon manufacturers like; Intersil, Techwell and Maxim are manufacturing new devices that offer greater cable distance; in some cases up 1600 meters on copper cable. Devices that compensate for high frequency cable losses and include automatic adaptive equalizers for varying lengths of cable. One manufacturer claims full signal recovery on 300 meters of cable. This means that the signal is the same quality at the end of a 300 meter length of cable as it was at the camera.

You have to ask why these leading international companies that manufacture silicon devices for many leading CCTV brands producing new analogue CCTV video devices? The answer is simple. CCTV camera and recorder manufactures are demanding these devices.

Is analogue CCTV a thing of the past?

I think not!

BFR Digital is always on the hunt for new technologies to implement in our products. Our products always feature the latest technology; watch this space for our next generation of Video CAT UTP transmission equipment.

IVSA-01R Specification Sheet

2011-01-29T11:21:00.002+02:00

Din-rail-mount enclosure for Fibre Lite and Fibre Lite Plus

2011-01-29T10:52:00.003+02:00

*** NEW PRODUCT ***

The LDIN-C is a din-rail-mount enclosure that can accommodate any Fibre Lite or Fibre Lite Plus cage card. This enclosure requires a 12Vdc power supply.

Compatible Part Codes:

Fibre Lite: LVTX-010-RMM, LVTX2-010-RMM, LVRX-010-RMM, LVRX2-010-RMM, LVTXD-010-RMM, LVRXD-010-RMM, LDTX-010-RMM, LDRX-010-RMM, LCTX5-010-RMM, LCRX5-010-RMM, LATX2-010-RMM.

Fibre Lite Plus: PVTX-010-RMM, PVTX2-010-RMM, PVRX-010-RMM, PVRX2-010-RMM, PVTXD-010-RMM, PVRXD-010-RMM, PDTX-010-RMM, PDRX-010-RMM, PCTX5-010-RMM, PCRX5-010-RMM, PATX2-010-RMM.

Fibre Lite stand-alone video and data link

2011-01-29T10:41:00.003+02:00

Single Pan/Tilt/Zoom (PTZ) camera, stand-alone, multimode fibre optic video and data link.

Fibre Lite stand-alone video link

2011-01-18T21:58:00.006+02:00

Single camera, stand-alone, multimode fibre optic video link.

VOTXD and VORXD

2010-11-04T11:03:00.003+02:00

BFR Digital launched the VOTXD and VORXD models at IFSEC Johannesburg 2010. These models feature the transmission of 8 video channels and 2 bi-directional data channels over a single fibre. This range is available for both multimode and single mode fibre optic applications. All video channels are digitally encoded using 8-Bit A to D encoders but is not compressed; delivering 8 high resolution images in real-time.

BFR at IFSEC Johannesburg

2010-11-01T21:01:00.004+02:00

Our IFSEC team. Silvana, Bruno, Charmaine and Dion. 1 September 2010

BFR at IFSEC Johannesburg

2010-11-01T20:58:00.000+02:00

Renato, Fernando and Bruno. BFR Digital’s three directors at IFSEC Johannesburg during stand buildup.

Success Story

2010-10-27T20:25:00.003+02:00

IVSA-01R was specifically designed for a customer that operates a remote video monitoring control room. The IVSA features 10 channels of video surge protection that starts clamping at 2.5 volts instead of the industry standard of 5 volts. This unit also features ground-loop isolation and one 10/100 Ethernet surge protection port.

Last week one of our customers sites was struck by lightning. Of the 52 channels of video on the site the 20 video channels connected to the IVSA units were the only ones not damaged.

VCSA-016R UTP Surge Arrestor

2010-07-20T15:19:00.002+02:00

BFR Digital releases the VCSA-016R. This product is a 16 channel UTP video surge arrestor for our Video CAT range of products.

PSU-250VA update

2010-07-13T21:04:00.001+02:00

The colour of the PSU-250VA has changed to black. The PSU-250VA is a 16 channel video surge arrestor and a 10Amp 24Vac Power Supply. The power supply features 16 outputs with individual surge protection and individually fused.

Fibre Lite Plus

2010-07-12T21:00:00.005+02:00

Here we have it! Fibre Lite Plus is now available. Fibre Lite Plus has been designed to transmit Video, Data, Contact Closures and Audio over multimode fibre optic cable. Fibre Lite Plus has ample power budget to achieve a cable distance of 6km.

Fibre Lite Plus transmits at 1300nm and features the same AGC functions as our popular Fibre Lite products.

Fibre PRO VQTXD and VQRXD

2010-07-03T12:16:00.001+02:00

BFR Digital launched the VQTXD and VQRXD models earlier this year. These models feature the transmission of 4 video channels and 2 bi-directional data channels over a single fibre. This range is available for both multimode and single mode fibre optic applications. All video channels are digitally encoded using 8-Bit A to D encoders but is not compressed; delivering 4 high resolution images in real-time. The data and video is transmitted simultaneously on a single fibre with the use of WDM technology. The data channels are available in RS422/485 and RS232.

VC-016PR update

2010-06-27T14:23:00.007+02:00

VC-016PR product update:

The colour of the VC-016PR has changed to black.

VC-016PR application note:

The VC-016PR is part of our Power CAT range. It transmits power to the camera and receives differential video from the camera. The VC-016PR delivers 0.5Amps per camera on a maximum cable length of 300m per channel over CAT5e cable. Each channel will require a VC-01PM, the VC-01PM features a DC-DC converter that supplies 12Vdc at 0.5Amp to power the camera and a differential video transmitter. One CAT5e cable is required per camera.

The benefits are:

Centralized power supply for the cameras
Lower labour costs
Lower cable costs
Lower conduit and cable path costs
Faster installation process
Better noise immunity
Ground loop isolation
Higher bandwidth cable
Longer cable runs (300m)

VSA-016R surge arrestor

2010-06-27T14:18:00.002+02:00

VSA-016R product update:

The colour of the VSA-016R has changed to black. The VSA-016R is a 16 channel video surge arrestor.

BFR Digital increases Warranty to 5 Years

2010-06-19T23:17:00.003+02:00

We are so confident in our fibre optic transmission equipment that we have increased our warranty on all fibre optic products from 2 years to 5 years. Our product has proven to be incredibly robust because it’s made in South Africa for African conditions.

Gautrain Solution from BFR Digital

2010-06-19T22:50:00.008+02:00

The first phase of the Gautrain opened last week and BFR Digital is proud to be involved with this world class project.

The Gautrain team required an enclosure to fit the cameras to their cable management system. The enclosure not only had to fit in with the aesthetics of the train stations but also had to manage the data, UTP video and feature a power supply for the camera. We engineered an enclosure with a single PC board that managed all these facilities for the camera. The enclosure also features video loss and power indicators. 360 of these unique enclosures were supplied for the first phase of the Gautrain project.

Contact Closures and New Field Lite Enclosure

2010-06-19T22:00:00.007+02:00

It’s been a busy year and I can’t believe that we are half way through June. We have finished development on the Fibre Lite Plus product range. Fibre Lite Plus is a multimode analogue link in 1300nm with enough optical power budget for 6km of cable. All the Fibre Lite (2.5km multimode) products are available in Fibre Lite Plus (6km multimode).

We have also introduced 2 new products:

This offers 5 inputs which are transmitted as data, then received and presented as dry relay output contacts at the receiving end.
Field Lite Enclosure. This enclosure features a 12Vdc 2Amp output, is battery backed by a 7AH battery, has a 12way splice cassette and 2 slots which can accommodate any Fibre Lite, Fibre Lite Plus or DTX Series cage card.

32 channel Fibre Lite video receiver

2010-04-22T22:26:00.005+02:00

Here we have it a Fibre Lite card cage populated sixteen 2 channel video receiver cards.

Fibre Lite 2 channel receiver card

2010-03-16T15:14:00.007+02:00

Hi there,

Sorry I’ve been out of the loop the last couple of months. I’ve been busy developing a new product range with my team. This is our first product introduction this year and in true BFR tradition it's built to last.

I’m proud to introduce the Fibre Lite 2 channel video receiver card. With this unit it is possible to populate the 2U Fibre-Lite cage card with up to 32 channels of fibre optic video receivers.

This receiver has Automatic Gain Control with a range of ±6dB and normalizes the video to a standard 1Vpp level no matter if the device connected to its composite video output is terminated at 75ohm or hi-impedance.

Keep watching this space for new procucts.

Digitally Controlled AGC

2009-06-04T08:39:00.009+02:00

AGC (automatic gain control) is nothing new and is used in a variety of equipment from CCTV cameras to fibre optic transmission equipment. When it came time to implement AGC in our Fibre Lite range of products we decided to do something really special with the AGC.

We analysed the sort comings of traditional Gain Control on analogue fibre optic equipment and found that the biggest problem was video drift. Simply put this is when the image starts losing its contrast, colour and eventually video sync (the image rolls on the screen). Video drift is caused by a number of factors like; cable aging, electronic component aging, large temperature fluctuations, additional losses on the cable due to the cable being damaged and requiring some splicing work, etc.

The Gain Control is there to compensate for all these variables but it’s normally a manual adjustment. This means that the system requires regular servicing by a qualified technician to maintain a crisp high resolution image.

We thought that in today’s world of high labour costs and the low cost digital microprocessors; why not have a microprocessor continually sampling, analysing and adjusting the gain control? This is how we come up with the idea of Digitally Controlled AGC. In our Fibre Lite range each fibre optic video receiver has its own dedicated microprocessor continually sampling, analysing and adjusting the gain control. Below is a simple diagram of how it’s done.

This is the magic behind Fibre Lite and what makes the product range adjustment free without digitally encoding the video as is the case with our Fibre Pro range.

http://www.bfrdigital.co.za/fibrelite.html

Can’t get Video Images from your IP Camera?

2009-05-20T11:06:00.008+02:00

I've been asked on several occasions to assist CCTV and Networking companies resolve issues with IP camera installations. The common fault I have encountered is that the system can view the IP camera settings on a web browser but it’s not able to view the camera images.

The common problem I encountered on all these installations is that the maximum CAT5 cable distance between the IP camera and the Ethernet Switch has been exceeded. Here is a table that I recommend:

If your installation needs to exceed the 100m limit then consider one of the following options:

Repeat the signal by installing another Ethernet Switch before the recommended maximum cable distance is achieved.
Consider installing fibre optic cable and fibre optic media converters.

BFR Digital Ethernet Switches: http://www.bfrdigital.co.za/switches.html

BFR Digital Media Converters: http://www.bfrdigital.co.za/dtxseries.html

Ethernet Surge Protector

2009-05-15T09:27:00.007+02:00

BFR Digital releases its new Ethernet surge protector.

Specifications:
Standard: 10/100Base-T
Nominal discharge: 5KA
Voltage limit: ≤ 40V
Response time: ≤ 1ns

Connectors: RJ45
Working temperature: -20 to 60°C
Not suitable for PoE applications

http://www.bfrdigital.co.za/

Twisted pair video transmission (UTP)

2009-05-13T08:44:00.004+02:00

This contribution is courtesy of my colleague Renato Bordin.

Video signals from cameras are transmitted to the receiving end via coax cables, normally RG59, RG11 and so on. The camera’s composite video output buffer has a series output resistance of 75Ω and requires an end of line load impedance of 75Ω, hence all video equipment such as matrices, DVR’s, monitors etc have a cable termination of 75Ω to match the cable and camera specifications. This transmission method is referred to as an unbalanced signal path and requires a return path which the coax cable provides in the form of the screen or braiding. The concept is the same as a light bulb connected to a battery with two wires, remove one wire and the bulb stops burning since there’s no electrical connection to complete the current flow. This method of video transmission has one major disadvantage; the video is referenced to ground making it susceptible to common mode interference and provides a path for potential differences between two ground points. This often results in poor quality pictures received on the monitor and when a lightning ground surge moves between the camera and monitor the potential difference is now at a dangerous level resulting in camera failure. Other disadvantages are the attenuation properties of coax cables, RG59 for example cannot reproduce a high resolution image at 300m, the high frequency attenuation, and hence the upper end of camera resolution is reduced. The net result is a high resolution camera installed for a particularly demanding application but the received picture is in fact more a medium resolution image. Bear in mind that most applications involve a digital recording device that further reduces picture content or resolution. Digital recording devices require the highest possible camera resolution or rather video bandwidth to reproduce an acceptable image after digitization and then compression.

The alternative to using coax cable as a video transmission medium is the twisted pair cable but we have some challenges to overcome. Let’s take a look at the most popular of twisted pair cables – CAT5e, widely available and well known in the IT industry. For starters the cable impedance is 100Ω and not 75Ω as required by a camera and has no screen, so induced common mode interference becomes a problem. More importantly the cable is designed for a balanced or differential transmission method such as Ethernet and RS485/422. In the active domain differential input and output operational amplifiers (Opamp’s) are used to convert an unbalanced signal to a balanced or differential signal appropriate for twisted pair transmission and visa versa at the receiving end. In the passive world a Balun transformer is used to match impedances. In simple terms this device receives video from a camera and converts it to balanced video matched for a cable impedance of 100Ω and the receiving end converts this balanced video signal back to its original format suitable for a coax connection to the DVR, matrix etc. There are only advantages in using CAT5e cable for video transmission. 1. Since we now have balanced video, common mode interference is rejected far more than coax, resulting in less noise present on the picture. 2. CAT5e cable frequency response specifications are ideal for video so longer cable runs are possible. RG59 cable runs must not be longer than 220m – 250m using high quality cable but CAT5e cable runs can be at the 300m mark and up. 3. Since CAT5e has 4 twisted pairs, one cable can carry 4 video signals. 4. Some twisted pair video solutions have full ground loop isolation. 5. Installation ease and costs are less than a coax based installation. I’m sure several installers reading this can see several other installation related advantages.

The VIDEO CAT range of products available from BFR Digital currently includes the VC-01, a direct camera mount twisted pair converter and the VC-016R. This is a 16 channel rack mount version with full ground loop isolation. Both products feature BNC’s for camera or head end video connections and terminals for twisted pair connections.

Renato Bordin

http://www.bfrdigital.co.za/videocat.html

February 2009 fly-fishing trip

2009-05-12T14:50:00.006+02:00

These pics are courtesy of my wife. They were taken earlier this year at Millstream Farm in Dullstroom. This is one of my favourite fly-fishing spots.

I had lots of luck with a dry line and an olive red-eyed damsel. I caught 19 rainbow trout that weekend but was only able to release 18.

Why AM modulated analogue multimode fibre optic video transmitters are smaller than digitally encoded multimode fibre optic video transmitters?

2009-05-11T08:50:00.011+02:00

I think the best way to explain this is with a few block diagrams and some photos. The block diagram below shows the basic design of a simple AM modulated fibre optic transmitter.

Our first fibre optic transmitter released in 2002 ran on this exact design and below I include a photo of this product’s PCB (Printed Circuit Board).

As you can see the design is so simple that the product is a mere 35mm in length.

A digitally encoded fibre optic transmitter is more complicated because all the video and data signals have to be converted into digital signals before they are processed and transmitted. The block diagram below shows the basic system design for this type of product.

As you can appreciate this is a far more complex design. The picture below is of our VTXD-030-SMM. When we designed the VTXD-030-SMM we decided to make the video transmitter and the video/data transmitter a one PCB design and only populate the component required for the particular model. It is for this reason that our video and our video/data units are the same size. This was done to simplify the product range and to decrease the cost of the product.

This product is 133mm in length, which is 98mm longer than the simple analogue design.

http://www.BFRDigital.co.za/fibre.html

BFR Digital Advert

2009-05-08T08:34:00.008+02:00

I am absolutely overwhelmed by this advertisement that our marketing team and our advertising agency put together. Please click on the advert above and have a look at it in its original size.

I think it’s fantastic. It delivers a simple and clear message.

Well done to both our marketing team and our advertising agency! :-)

Let me know what you think.

Field-Lite Termination Enclosure

2009-05-05T12:06:00.007+02:00

This is one very cool piece kit!!! 4 multimode video transmitters, 1 multimode data receiver with power supply and splice cassette in one field enclosure.
When I first designed the Fibre Pro Field Termination Enclosure (FIELD-ENC) I never thought it would be as popular as it is. This popularity has led to the DTX-Adaptor, which is an adaptor plate to accommodate the DTX Series equipment in the FIELD-ENC.

Now with the Fibre-Lite Field Termination Enclosure (FIELD-LITE), I took a completely different approach. As you can see, I designed this product to be modular. The base of this product is a motherboard which includes the power supply for the transmitter/receiver fibre optic modules; 4 output data channels to control PTZ cameras and a 12-way splice cassette. On to this motherboard, up to 5 multimode fibre optic modules can be plug-in. The modules could be 5 video transmitters OR it could be 4 video transmitters and 1 data receiver. The data from the data receiver is distributed and offers one output per video channel. All this is housed in a IP55, self-extinguishing plastic enclosure according to IEC60695-2-1 standards.

http://www.BFRDigital.co.za/

Point-to-Point Asynchronous Transmission

2009-05-05T10:13:00.012+02:00

The objective of this posting is to try and explain why our DTX Series of products do NOT require any IP addresses in the simplest way I can. The DTX Series range of BFR Digital products offers Point-to-Point Asynchronous Transparent Transfer of data.

Let’s break this down into 2 separate parts:

1. Point-to-Point

Point-to-Point is the simplest network topology and is merely a permanent network connection between two network end points. The simplest comparison is that of a tin-can telephone.

2. Asynchronous transmission

Asynchronous transmission is a data link protocol primarily used for point-to-point network topologies. Data is transmitted between the two network end points and an indefinite amount of time may lapse between the transmission of data packets. The data packets are prepared for transmission by encapsulating the data. This encapsulated packet of data is called a frame. Then a start bit is placed in front of the frame, this start bit alerts the receiver to the incoming data. At the end of the frame a stop bit is included and this tells the receiver that it is the end of the incoming data. The one step missing here is the portion with the error handling but for the purpose of this explanation we will ignore this step.

Let’s say that you want to transmit a data packet from IP address 192.168.1.10 to IP address 192.168.1.15 over a DTX fibre optic link. The DTX link will transmit all data presented to it regardless of the final IP destination. The IP address along with its data will be encapsulated into a frame and transmitted from one end of the link to the other. On the receiving end the encapsulation is removed and the destination IP address and its data are presented to the receiving end of the network in its original state. This is why the DTX Series of products do not require their own individual IP addresses and behave as though the link were just a simple CAT5 cable linking two network end points.

http://www.BFRDigital.co.za/

Laser Emitters

2009-04-21T12:41:00.014+02:00

Earlier this month I was asked to assist a customer with a 32 link, DTX Series system. The customer failed to understand what transparent point-to-point transmission actually means and I will be addressing this in my next posting.

What I do want to talk about is safety precautions that need to be taken when working with fibre optic transmission equipment that use Laser Emitters. Both our Fibre Pro and DTX Series use laser emitters. These Lasers provide stimulated emission, i.e. they are on all the time.

The Fibre Pro and DTX Series products emit intense infrared light at 1310nm and 1550nm which is invisible to the human eye. This radiation can permanently damage the retina of the human eye. The diagram below shows the visible and invisible light spectrum.

All Fibre Pro and DTX Series products are packaged in antistatic bags that are sealed with a cautionary notice. Please read the notice before tearing the seal. The notice is there for your safety.

Please take the following precautions:

Never look into the source or the fibre cable.
Never power-up the source useless the fibre optic cable is connected to it.
Always keep the protector cap on the source if no fibre optic cable is connected.
Be cautious!!!

Fibre Pro

DTX Series

www.BFRDigital.co.za

Calculating - Fibre Optic Power Budget

2009-04-19T20:20:00.024+02:00

Calculating the Optical Power Budget for a fibre optic cable link is really simple. Firstly, we need to start with some known facts. The losses quoted below are the norm but you can obtain the cable and connector losses from your local cable manufacturer for a more accurate calculation.

Let’s look at the following example:

1. Calculate the Cable Loss
Cable loss = Cable Distance x Cable Loss per km
Cable loss = 2km x -2.5dB/km
Cable loss = -5dB

2. Calculate the Connector Loss
Connector Loss = Connector Quantity x Connector Loss
Connector Loss = 2 x -0.5dB
Connector Loss = -1dB

3. Calculate the Splice Loss
Splice Loss = Splice Quantity x Loss per Splice
Splice Loss = 2 x -0.2dB
Splice Loss = -0.4dB

4. Calculate the Total Link Losses
Total Link Losses = Cable Loss + Connector Loss + Splice Loss
Total Link Losses = -5dB + -1dB + -0.4dB
Total Link Losses = -6.4dB

We have now successfully completed the first part of the calculation and we have established that the total loss on this fibre optic link is -6.4dB. The second part of the calculation is even simpler because most manufacturers of fibre optic transmission equipment quote the Optical Power Budget in their spec sheets. For example the Optical Power Budget for the Fibre Lite Range of products is -12dB. Alternatively, we can calculate the Optical Power Budget:

Transmitter Output Power (LVTXD-010-SMM Fibre Lite) = -14dBm (quoted by the manufacturer)
Receiver Sensitivity (LVRXD-010-SMM Fibre Lite) = -26dBm (quoted by the manufacturer)

Optical Power Budget = Output Power - Receiver Sensitivity
Optical Power Budget = -14dBm - (-26dBm)
Optical Power Budget = 12dB

Power Margin = Optical Power Budget – Total Link Losses
Power Margin = 12dB + (-6.4dB)
Power Margin = 5.6dB

It is good practice to allow for a Power Margin of 3 dB. This allows for cable degradation and should you ever have the misfortune of having the cable damaged or cut you still have enough Budget to re-splice the cable.

www.BFRDigital.co.za

Fibre Lite

2009-04-16T20:52:00.005+02:00

We at BFR Digital have just completed our Fibre Lite product range. This range of products caters for the transmission of CCTV video signals and unidirectional data signals over multimode fibre optic cable. Fibre Lite offers an optical budget of 12dB; which means a maximum cable distance of 2.5km and a system safety margin (excess power margin) of 3dB.

This product range is the first in its class to feature Digitally Controlled AGC; this feature automatically adjusts the AGC to compensate for optical cable degradation and other insertion losses. Each video receiving channel has it own dedicate processor that continuously samples and adjusts the AGC.

In true BFR Digital fashion the Fibre Lite range is designed to be robust and easy to use; for this reason the Fibre Lite range is offered with a 2 year warranty. We achieve this robustness and reliability by over engineering our products.