Difference between Optic Modem and Media Converter

Difference between Optic Modem and Media Converter

Fiber Optic Modem

Fiber Optic Modem, also known single-port optic multiplexer, is a point-to-point type terminal equipment which uses a pair of optic fibers to achieve the transmission of E1 or V.35 or 10base-T. Fiber modem has the function of modulation and demodulation. Fiber modem is local network relay transmission equipment, suitable for base station transmission fiber terminal equipment and leased-line equipment.

Fiber modem is similar to the baseband MODEM (digital modem). The only difference from baseband MODEM is that it access fiber line, the optical signal. The multi-ports optic transceiver generally called multiplexer. For multi-port optical multiplexer is normally be directly called “multiplexer”, single-port multiplexer is generally used on the client, similar to commonly used WAN line (circuit) networking with the baseband MODEM, and also named for “fiber modem”, “optical modem”.

Fiber Media Converter

Fiber Media Converter is a simple networking device making the connection between two dissimilar media types become possible. Media converter types range from small standalone devices and PC card converters to high port-density chassis systems that offer many advanced features for network management.

Fiber media converters can connect different local area network (LAN) media, modifying duplex and speed settings. Switching media converters can connect legacy 10BASE-T network segments to more recent 100BASE-TX or 100BASE-FX Fast Ethernet infrastructure. For example, existing half-duplex hubs can be connected to 100BASE-TX Fast Ethernet network segments over 100BASE-FX fiber.

When expanding the reach of the LAN to span multiple locations, media converters are useful in connecting multiple LANs to form one large campus area network that spans over a limited geographic area. As premises networks are primarily copper-based, media converters can extend the reach of the LAN over single-mode fiber up to 160 kilometers with 1550 nm optics.

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Wavelength-division multiplexing (WDM) technology in the LAN is especially beneficial in situations where fiber is in limited supply or expensive to provision. As well as conventional dual strand fiber converters, with separate receive and transmit ports, there are also single strand fiber converters, which can extend full-duplex data transmission up to 120 kilometers over one optical fiber.

Other benefits of media conversion include providing a gradual migration path from copper to fiber. Fiber connections can reduce electromagnetic interference. Also fiber media converters pose as a cheap solution for those who want to buy switches for use with fiber but do not have the funds to afford them, they can buy ordinary switches and use fiber media converters to use with their fiber network.

Main Difference between Media Converter And Optical Modem

The difference between the media converter and optical modem is that the media converter is to convert the optical signal in the LAN, simply a signal conversion, no interface protocol conversion. While, fiber modem for WAN is the optical signal conversion and interface protocol conversion, protocol converter has two types of E1 to V.35 and E1 to Ethernet.

In fact, as the developing of network technology, the concept of media converter and fiber modem has become increasingly blurred, which are basically can be unified for the same equipment. Media converter becomes the scientific name of fiber modem.

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Few things need to know, There are two primary types of fiber optic cable, single mode fiber (SMF) and multimode fiber (MMF). The former has a very thin core about 5-10 microns in diameter, which is about 10 percent of the latter. Generally, single-mode optical fibers used in telecommunications operate at 1310nm or 1550nm wavelength while multimode fiber at 850nm and 1300nm. However, sometimes, the subdivision of the two types is different due to various fiber optic cable manufacturers. single mode optical fiber cable is used for longer distances such as 100km compared with multimode fiber under 2km due to the smaller diameter of the fiber core. Therefore, single mode optical fibers are typically used outside between buildings in cable TV, internet, and telephone signals transmission while multimode fibers are used within buildings in backbone applications such as computer network linking.

Normally, fiber optic cable speed rates at 10 Gbps, 40 Gbps and even 100 Gbps.

Generally, one fiber optic cable is made up of incredibly thin strands of glass or plastic known as optical fibers (called “core”) surrounded by an insulated casing (called “cladding). Each strand is a little thicker than a human hair and can carry much data like 25,000 telephone calls. Therefore, an entire fiber optic cable can easily carry as much data as you can imagine.

720p and 1080p explained

720p explained

720p is the shorthand name for a category of HDTV video modes. The number 720 stands for the 720 horizontal scan lines of display resolution (also known as 720 pixels of vertical resolution), while the letter p stands for progressive scan or non-interlaced.

Progressive scanning reduces the need to prevent flicker by filtering out fine details, so sharpness is much closer to 1080i than the number of scan lines would suggest. A 720p frame has about 1 million pixels. Compared to it, a 1080p frame has 2 million pixels so the amount of detail doubles. However in practice the difference between 1080p vs 720p is not as obvious as the one between standard definition vs high definition (480p vs 720p). For example a regular DVD isn’t even considered high definition because it is either 720×480 (NTSC) or 720×576 (PAL) but it looks much better than regular NTSC or PAL TV broadcasts and not as great as 720p. That being said, you do get more detail from 1080p than from any resolution if you have the “winning” formula for screen size, resolution and viewing distance – that is if you have the optimum conditions to get the most out of 1080p.

1080p explained:
The number 1080 represents 1,080 lines of vertical resolutions (1,080 horizontal scan lines), while the letter p stands for progressive scan (meaning the image is not interlaced). 1080p can be referred to as full HD or full high definition although 1080i is also “Full HD” (1920×1080 pixels). The term usually assumes a widescreen aspect ratio of 16:9, implying a horizontal resolution of 1920 pixels. This creates a frame resolution of 1920×1080, or 2,073,600 pixels in total.

The only pure 1080p content comes from high definition DVDs like Blue Ray and HD DVD. Regular DVDs are way below that, having just 480p or 576p. You also get HD content from TV broadcasts but for now only 1080i and 720p. Basically 1080i offers pretty much the same amount of detail as 1080p but the quality of fast moving scenes is a bit inferior to 1080p. To understand this better read the 1080p vs 1080i guide. 720p content will of course look the same (or very similar) on a 1080p screen as it does on a 720p screen because what also matters is the content resolution not just the screen resolution.

Here is a sample with the difference between 720p and 1080p:

480i - Total image resolution 337,920 pixels

480p - Total image resolution 337,920 pixels

720p - Total image resolution 921,600 pixels (roughly equivalent to a 1 mega pixel camera)

1080i - Total image resolution 2,073,600 pixels (equivalent to a 2 mega pixel camera)

1080p - Total image resolution 2,073,600 pixels (equivalent to a 2 mega pixel camera)

More lines is nice but don't forget about the 'p' and 'i' in the 720p, 1080i and 1080p. The letter is an abbreviation for the type of scan the TV uses -- 'p' stands for progressive and 'i' stands for interlaced.

HD-TVI, HD-CVI, HD-SDI, HD-AHD, Analog & IP Camera

HD-TVI, HD-CVI, HD-SDI, AHD, Analog & IP Camera

Even we enter into digital era, analog surveillance technology doesn't stop its innovation. Besides the HD-SDI and HD-CVI (in house technology of Dahua), today the Hikvision and other camera manufacturers announce HD-TVI cameras release.  HD-TVI means High Definition Transport Video Interface,  HD-TVI is based on traditional coaxial cable for video and data transmission, it supports not only 720P/1080P video signal, but also including audio, data signal over long distance up to 500 meters.

At present, there are approximate 100 million coaxial cables are deployed for analog camera connection. In the next 3-5 years, they will be replaced with high definition camera. However, some users start to worry they have to rewire, re-install or add new network devices for upgrading. This group of users prefer the economical and easy solution to upgrade existing system to HD, rather than adopting the IP camera. In this context, the HD-SDI and HD-TVI technologies were born.

HD-TVI advantages

500 meters long range video transmission:-

As we know, HD-SDI and conventional analog solutions only has limited 100 meters video transmission. Additionally, the cost of HD-SDI equipment is more expensive. The HDTVI technology (HikVision) offers long range distance video transmission at 1080P/720P through coaxial cable.  The cost of HD-TVI products is very affordable, permit users upgrade the system with minimum investment. This makes HDTVI become a perfect solution to fit all analog surveillance applications. Furthermore, the new HDTVI technology support UTC function which can allow user to remotely control the OSD menu and PTZ control via coaxial cable. This means user can quickly install and adjust the camera without accessing the camera itself.

HDTVI Camera with CS 4mm lens

Analog high definition resolution at 720P/1080P:-

Similar to HD-CVI (in house technology from Dahua) and HD-SDI, the new HDTVI cameras can deliver real time 720P/1080P HD resolution video without video latency. The HDTVI DVRs support full time 720P/180P video recording and playback. Through using HDTVI compatible cameras and DVRs, user can setup a complete new HD analog surveillance system or easily upgrade the existing conventional analog system to HD surveillance system.

HDTVI Camera with CS 12mm lens,

Broad manufacturers to offer great compatibility:-

HDTVI equipment is HDTVI open standard, which guarantees trouble-free connection to other HDTVI-compliant cameras and DVRs. By the way, the new designed HDTVI DVR also can support traditional standard video camera for offering great flexibility.  All HDTVI HD cameras can access third party DVRs equipped with HDTVI technology from other manufacturers. The main HDTVI members including TVT, Hikvision, Hisharp, Unifore, LSVT...etc.

HD-TVI vs Analog

In summary, the advantage of HD-TVI compared with Analogue is:

1.       HD resolution on 720P/1080P at 25/30fps

2.       Long distance transmission for HD video

3.       No video quality loss and delay for transmission

HD-TVI vs HD-CVI 

Obviously, HD-TVI and HD-CVI have very similar features, both of them can provide analog high definition solutions. HD-TVI derives from American based company that does not supply to only one manufacturer. Therefore we are expecting many analog camera manufacturers will release wide range of HD-TVI based cameras to market. Therefore, HD-TVI is more likely to become an industry standard, not a proprietary technology/solution.

HD-SDI vs HD-CVI 

HD-TVI vs HD-SDI 

In conclusion, compared with HD-SDI, new HD solution with advantages of:

1.       Longer video transmission distance up to 1000ft (300m) over regular coaxial cable

2.       700ft (200m) distance for video transmission over UTP (Cat5, twisted cable)

3.       More cheaper price for analog HD system

4.       Support twisted cable installation

HD-TVI vs IP Camera

Hence, compared with IPC, the advantages of HD-TVI are

1.       No network bandwidth requirement/influence

2.       No network configuration, as easy as analog system

3.       No video quality loss and compression

4.       No video latency issue, real time live-view

5.       Long video transmission distance

6.       More affordable price for camera and video storage devices

AHD advantages

A new kind of camera: AHD Camera (Analog high definition)/HD-AHD is developing so soon in the market now.
The price is similar as Analog camera and the image effect is similar as digital camera!

The Advantages of AHD Camera:
1) AHD Camera can link with general DVR and the resolution is looks like 1000tvl analog cameras.
2) AHD Camera can link with AHD DVR, and the resolution is Megapixel High Definition ( Now have 1MP, 1.3MP already).
3) Transmit by Coaxial cable-500m!!
4) The price is similar as Analog system no matter considering DVR or camera.

HD-CVI cameras vs HD-AHD cameras

1.       1.0 megapixel AHD camera adopts OV9712 + NVP2431H solution (CMOS Chip: OV9712 & DSP Chips : Nextchip NVP2431H), while HD-CVI camera adopts the PO3100K + DH9801 solution. In addition to the difference of solution, the price vary greatly, OV9712 + NVP2431 of AHD camera module only costs US$7.5, and PO3100K + DH9801 camera module costs approximate US$11.

2.       AHD camera can connect to CRT display directly, the image can display properly. HD-CVI camera connects to traditional CRT, it doesn't show images. For video live view/recording/playback, HD-CVI cameras need to work with HD-CVI DVR. It seems, the HD-AHD cameras support 960H output mode, which is very convenient for test and installation. Since the AHD cameras can be backward compatible with all traditional analog equipment. Compared with HD-CVI, it has advantages of great compatibility.

3.       Competiable with normal D1 / 960H, and analog peripherals (including distributors, matrix, etc.). Switch AHD, IP and Anolog video signal from AHD DVR in no time.

4.       Strong anti-interference capability & solid interface protection that can avoid space high frequency electromagnetic radiation to ensure a constant signal transmission of high definition video display without problems as frame drop and lock loss occurred.

Visit: HD-SDI High Definition CCTV vs Traditional CCTV Cameras

360p, 480p, 720p, 1080p Measure Up

360p
This is an Animoto video’s default resolution. The majority of YouTube and Hulu videos are displayed in 360p, so that’s about the video quality that 360 lines of resolution provides. This (as well as the 480p) is a great resolution for mobile devices since the mobile screen rarely has enough pixels or enough memory to support HD videos.

480p

640x480 (480p) is the resolution that almost every camera can shoot at, most digicams from the last two years shoot at least 480p. Although there are lower resolutions (typically for high speed video), 640x480 should really be the lowest resolution to consider. 640x480 is a pretty good resolution, its not HD but its the resolution of standard definition television (SDTV) and a good quality source at 480p can look pretty good. Most people will be happy with this resolution but those who love the idea of widescreen, high definition home movies will want to venture into the two HDTV options. A 480p video will play beautifully on both your laptop and desktop monitors, and though it isn’t quite HD, it is definitely good enough to view on that spiffy new flatscreen TV you just bought

How does 480p Measure Up?

§  480p vs 720p: 480p has 1/3 the resolution

§  480p vs 1080p: 480p has about 1/7 the resolution

§  Click on the full resolution sample and you'll see that a clean 480p image can be fantastic - DVD is after all "only" 480p

720p (1280x720)

1280x720 (720p) is the lowest of two HDTV resolutions. The ability for digital cameras to shoot high definition video started to pick up in 2009 and is now available on many cameras. 720p provides fantastic video quality that is perfect for large screen TVs and high definition home movies. An HD 720p Animoto video is crisp, sharp, and takes full advantage of any display you want to view it on

How does 720p Measure Up

§  720p vs 480p: 720p has 3X the resolution

§  720p vs 1080p: 720p has about 1/2 the resolution

§  720p is a fantastic high definition resolution to shoot at

 1080p (1920x1080)

1920x1080 (1080p) is the highest of two HDTV resolutions. 1080p is also known as Full HD and is very high resolution video. Because of it's extreme size it requires more storage space, faster computers to edit, more powerful camera processors and a very large TV to notice the difference. Currently 12 of 500 cameras released in the last 2 years shoot 1080p

How does 1080p Measure Up?

§  1080p vs 480p: 1080p has 7X the resolution

§  1080p vs 720p: 1080p has about 2X the resolution

§  1080p is a fantastic high definition resolution to shoot at

§  1080p is the pinnacle of HD quality - but more suited for pros and hard core enthusiasts.

High Definition Formats (I.E. HDTV):

720p - The Resolution is 1280x720 pixels, sent at 60 complete frames per second.

1080i - The Resolution is 1920x1080 pixels, sent at 60 interlaced frames per second or 30 complete frames per second.

1080p - The Resolution is 1920x1080 pixels, sent at 60 complete frames per second.

Capturing Crystal Clear Images With Megapixel Technology

Megapixel surveillance is not a new concept — its applications and benefits are starkly clear. What has changed are smarter cameras, taking advantage of the added pixels and a better understanding of illumination in real life. In the first of a two-part report, A&S examines how smarter megapixel cameras are getting; the second part looks at best practices for optimal performance.

The big picture for megapixel surveillance cameras looks bright, in the wake of the recession. HD and megapixel cameras are expected to make up nearly 30 percent of network camera shipments in 2011, according to IMS Research. By 2015, it is forecast that more than 60 percent of network cameras shipped will be of megapixel resolution.

The resolution increase has a noted effect on the whole surveillance system. While a 2.1-megapixel or 1,080p HD image is six times larger than a D1 image, the additional pixels require a bigger pipe to transmit more data. The infrastructure and storage costs for megapixel are well-documented, with ROI and TCO being used as arguments in favor of bigger pictures. The fate of megapixel is linked to the future of IP networks, with HD forecast to make up most high-resolution cameras compared to megapixel, according to IMS.

Megapixel surveillance requires careful planning, but the benefits of added resolution boost the accuracy of analytics. Edge devices take advantage of faster processors, resulting in smarter use of pixels. Analytics can help reduce bandwidth, as an event will trigger video streaming, rather than constantly sending the same still images over the network. A more distributed architecture puts less strain on networks and makes life easier.

Clarity is the main driver for megapixel. “At the end of the day, you're putting in a security system to protect life and provide evidence in a court of law,” said Stephen Moody, Security Development Manager for ViS Security Solutions, an integrator in Ireland.

Cracking the Code
H.264 is the de facto standard compression for megapixel cameras, due to its efficiency in crunching large data files into smaller ones for transmission and storage. As compression evolved from M-JPEG's stills to MPEG-4 and now to H.264, a variety of profiles yield differences in performance. With 17 profiles in all, three are the most common: baseline, main and high, said Sachin Khanna, PM for CCTV, Bosch Security Systems.

By profile, the baseline is appropriate for video conferencing; the main profile is good for broadcast video; and high profile is most applicable for HD broadcast video. “H.264 requires a fair amount of processing power for encoding and decoding; this may limit the camera's frame rate and dictate the NVR platform to achieve the desired performance,” said Rich Pineau, CTO of Oncam Global.

Most H.264 profiles stem from 2-D applications, with not all profiles being capable of integration. “Even if both cameras are H.264 and the manufacturers are partners, the system could still not work,” said Patrick Lim, Director of Sales and Marketing for Ademco Far East. “The I/O and output are hard to integrate. Some engineers say it's easy to plug and play — there's no such thing.”