Talk:Infrared Leds, Cameras, DC-DC converters etc
Request for comment: I will discuss various ways of using DSLAMS, Video baluns , copper, Telephone poles and fiber to setup a neighbourhood surveillance system.
Slice the street up into multiple camera zones
Three cameras should be trained down the length of the street. One to monitor only the tar road and the other two to monitor the pavements. Motion detection works best the narrower the zone is to be monitored. Multiple cameras can be spanned adjacent to each other, thus slicing up the road into as many sections as desired. Plant to poles on the pavement and suspend the camers at a certain height across the road. It is critical that nobody's privacy is invaded with such a setup, with each resident able to see each camera output this will be ensured.
DSLAM and video baluns
A DSLAM overcomes the distance limitation of 100m over copper wire that limits Ethernet usage. Distances of over 5km are possible over a twisted pair telephone copper wire. A single DSLAM port uses the ATM protocol to transmit fixed width packages to an ADSL modem. The Ethernet protocol uses variable data rates. As the distance of a wire increases, its resitance increases hence the the need for the ATM protocol for long distance transmission. DSLAM is a viable alternative to many Fiber deployments. A DSLAM allows people to build their own private telephone exchanges via telephone poles in the exact same manner that Telocos build theirs.
Let's focus on pure analogue video transmission over a distance of 1km. A video balun transmitter converts the analogue signal to digital over twisted pair copper, transmits it over 1km to the receiver which converts it back to analogue. These analogue signals are brought back to a central control room connected to Zoneminder boxes. The Zoneminder video stream are uploaded to the DSLAM besides it. The Adsl2+ Dslam can stream 24meg on a single port. Thus every person with an Adsl modem can access all the camera streams centralised at the Zoneminder PC's. By daisy-chaining Dslams cheap copper can be used to extend the streams instead of using Fiber - it depends on various factors.
See *DsLam http://en.wikipedia.org/wiki/DSLAM
