riggstech

In responce to AK357, IEEE-802.3af states that the Power Sourcing Equipment PSE can choose either Variant A, which places power on lines 1,2,3 ,6 or Variant B lines 4,5,7,8. A Powered Device (PD) that is IEEE-802.3af compliant must be able to accept power from both sources. Also within the IEEE-802.3 standard the PD device must accept positive or negative on either lines. From our research we found that most Injectors and Mid spans use Variant B with Positive power on Pins 4.5 and Negative power on 7,6. Network Switches with PoE seem to use Variant A. Cisco also uses Variant B but with Positive power on 7,8 and Negative power 4,5. But all this has nothing to do with the bandwidth of Ethernet per say. Yes unclean power can foster cross talk which can effect things. james.

IEEE placed a standard on PoE. 802.3af and soon 802.3at. With in this standard the medium voltage is 48vdc, with a max of 450mA of power. 802.3at ( PoE Plus) max of 700mA ( which is being debated on). Also long as the device is a IEEE-802.3af compliant there is no issues wtih power. A side note, numerous low end PoE switches are not providing enough power to all their ports. Normally a 4 port would need 60 watts of power to be fully compliant, but if you read the actually power for the unit, it about 30 watts, half of what is need. Just keep in mind about power budgeting.

We are a competitor of Veracity. We offer a 2 port outdoor rated and 5 Port outdoor rated. We also have a PoE Camera Enclosure. Both technology must be placed at the 328 feet (100 Meters) mark. Both technology are 802.3af compliant. Veracity focus on the indoor market, and we focus on the outdoor. We currently can reach 2296 feet from the original network drop, while still offering up to 9 watts of power to any 802.3af PoE network device. We are distributed threw Anixter and Northern Video

There are a number of open source video analytics. and plenty of white papers if you like to read the math behind the analytics. ZoneMinder..but be ready to play inside of linux.

Video analytics, can do some very cool things, if set up correctly. I helped write and design software for 2 different VA companies. It takes some getting use to. Patience is the key. Don’t expect the system to do every thing. Expect False Positives. You will be setting for hours watching video. Different times of the day give you different shadows. Glares off metal and moving objects can throw system off, setting off false alarms. When setting up a system, use a fixed camera to detect and PTZ to interrogate. There are different types of alarm rules. Video based rules and Map based rules. Each has their own unique problems. Try placing the cameras in an area were there is not so much background movement…Traffic from cars on roads. When placing the camera make sure there is plenty of room for the object to be detected, Target-on-Pixel ratio. Make sure you have plenty of bandwidth. Manage your customer’s expectations; VA doesn’t not remove the need for live guard. Just allows the guard to stay better focused. Hope this helps a little.

IEEE has stated that Ethernet distance limitation is 328ft (100m), once past that point the degradation of Ethernet starts to happen. Ethernet extenders help combat this. Some manufactures use a DSL type modem on both sides, but have a Bandwidth limitation. Some use a Power-over-Ethernet style, were a 10/100 mbs switch powered via PoE is placed every 328 ft to continue the Ethernet signal. There is also Cat5 cable that uses 22AWG cooper that also helps with distances, but limited to another 50-75 feet more.