Soundy

And how many angels can dance on the head of a pin? The problem with trying to fill in something like "airports on average have x% of motion" is that there's nothing to base it on. First of all, what size airport? How many passengers do they actually move? What sort of time frame are you averaging on - per week, month, season, year? Are you accounting for high-traffic periods like holidays and long weekends? How about things like major flight cancellations caused by weather or other events, that can lead to more people simply milling about the terminal for extended periods? And even if you can average that out, your individual installation will vary depending on camera placement, FOV, other non-passenger movement in the area (I've seen recordings run all night long because someone put up a hanging sign that triggered recording every time the HVAC kicked in - something that wasn't expected when the motion masking was initially set up). Things like headlights of cars going by at night, shining in through windows, can trigger recording as well - there's no way to average that across different sites. If it's that big an issue to get it ACCURATE, it may be necessary to just monitor the traffic patterns yourself for a specific installation. Make up a mobile rig with a netbook and one or two IP cameras, set it up in the desired area with guestimate(s) of the desired coverage(s), and check the motion percentages for yourself.

HAHAHAHAHAHAHAH! Oh wow, thanks, I love to start the day off with a good laugh. Simply slapping an IP interface on a junk camera does not magically imbue that camera with "value". IP is just another way to get the picture from the camera to the recorder. If the camera has a crap picture, it's "low value", regardless of the transport medium. HAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHAHAHAHAHAHAHAHAHAAHA

Is it just me, or does all this look like a setup?

Not even close. CR2032 = 20mm diameter, 3.2mm thick ML621 = 6.8mm diameter, 2.1mm thick http://en.wikipedia.org/wiki/Button_cell#Package_size

RS485 typically has terminals labelled RX(A) and RX(B) for receive, TX(A) and (B) for transmit... in the case of the camera, you only need to receive, so they may simply be marked A and B. Some also mark them as RX+/RX-. On the RS232 serial port side, you're only sending, not receiving... so you'll only use pins 2 and 5. I find it USUALLY works to connect pin 5 to RX(A) and pin 2 to RX(B), but the odd time you need to reverse it, and sometimes you need to power up the camera with it connected one way, then hot-swap the wires. But those tend to be the rare cases and I've mostly seen it with older cameras.

Before you even start to think about servers you need to decide on your frame rate from each camera, the resolution of the images and how long you intend to store the images (may be different for each camera depending on the operational requirement). Then consider how you are going to deal with time synchronisation, security and redundancy. Consider spare parts, operating software and how you are going to deal with bulk disk replacement at the end of year three, power consumption, power conditioning and cooling. Only then should you be thinking about which server to use Ilkie QFT. Your question is like asking "what kind of car do I need" without first answering what you need it FOR.

Analog cameras themselves actually only give you a new image every 1/25 or 1/30 (depending whether they use PAL or NTSC video standards, respectively). They do this simply because those are the specs of those standards, and all equipment must conform to it if cameras and recorders are to be able to talk to each other.

I'll second the vote for 3xLogic Vigil - we use their systems almost exclusively, and they're the system of choice for two of Canada's largest oil companies and at least one major upscale restaurant chain that we service (gradually replacing all their GV systems, BTW). One of the benefits of this route is that all Vigils are hybrid systems, so you can plug your analog cameras into them now, and add/change to IP cameras later. 3xLogic does sell their own line of IP cameras (rebranded Hikvisions), but Vigil does work with most other IP cams out there. They have a number of advanced features that may be useful to your needs - some I've used (like the VCM and remote client), some I haven't had call for yet (like central database and redundant DVRs).

I hope their cameras are better than their ad copy... "This is a perfect 90 degree corner mount color camera which includes tamper resistant screws. The camera features 420 line resolution, 1/4"" CCD format and 2.9mm lens. It has a built-in electronic shutter behind a 16 gauge steel face plate. Also available with 480 line resolution and ExView 2.5mm lens: CVC-607EXCM/2.5" In our case, we just repurposed a used Extreme dome... I don't see the point of the IR in the Conway offering; any elevator should already be well-lit to comply with safety codes.

I'm not aware of anyone who makes a camera SPECIFICALLY for elevators. You'll have a hard time finding a minidome with a 1/3" sensor, or a 2.2mm M12-thread lens, but even a 1/4" with a common 2.6mm lens will give pretty much full coverage of the elevator. That's what we have in this installation:

AC is usually defined as a sinusoidal waveform of alternating current (positive and negative current). But not all sinusoidal (or complex multi-frequency sinusoidal) waveforms are Alternating Current. I think very little current is actually being sent in the case of a TV video signal. And if I believe this: http://electronics.howstuffworks.com/tv9.htm then it's all positive voltages - so no negative currents, so not an AC signal. Depends on how one looks at it, or in some cases how the circuit is designed... it could also be an AC signal with a DC offset. In any case, if one wanted to check the voltage of the video signal, one would need either an O-scope, or a P-P voltage meter - most basic multimeters wouldn't get a proper reading on either DC or AC settings.

Disclaimer: the following advice will apply to MOST common professional-grade PTZ cameras. It may or may not apply to cheap consumer or offshore no-name units. You can use a USB-to-RS232 serial adapter, readily available for cheap, to connect a laptop to the camera, set up your autoscan, and then leave it run. As in the disclaimer, this may depend on the particular camera's autoscan capability. You'll need some appropriate software as well; I regularly use one called PTZ Controller, available from www.serialporttool.com There are too many to name, as most manufacturers have their own proprietary protocols. However, most (almost all) professional cameras support Pelco D and/or P protocols, as do the vast majority of controllers, software, and PTZ-capable DVRs. I wouldn't say "ANY" but the vast majority will work. Some DVRs will have RS-232 instead of RS-485, in the form of a standard DB9 male connector; this can be wired directly to most cameras that support RS-485 and will work just fine over shorter runs. For the exact WHY you'd probably have to ask the designers, but some possible reasons: - PTZs are more expensive overall, so using 1/4" sensors keeps costs down a bit. - A smaller sensor allows a smaller camera and a smaller lens with a greater overall zoom factor. - A smaller assembly allows for a more compact camera. - A smaller assembly is also lighter, which allows the camera to be more responsive while using cheaper, more efficient motors. There are 1/3" PTZs, like the Pelco Esprit, but those are generally a similar design to what you have now - a standard housing with a box camera inside (although they don't use the troublesome coiled cable). These also tend to be SUBSTANTIALLY more expensive than their smaller dome counterparts, as they have larger cameras, heavier housings, and thus require more powerful motors. Try finding a used Pelco Spectra II or Spectra III, or perhaps a Capture FasTrax II. These are solid cameras that I've used, and they work fine with Pelco D/P protocols. If you want something smaller, look for a Capture MiniTrax. One other thought: if your DVR supports it, and depending on the area to be covered, consider a 3MP or larger IP camera with a wide-angle lens, or something in a multi-lens panoramic camera (see Capture OmniScape or various Arecont offerings). Then you don't have to worry about something happening in one area while the camera is pointed somewhere else... you just record the whole area, all the time, and zoom in later.

You could do it off a computer using a standalone app like PTZ Controller from www.serialporttool.com

You could try the T-adapter first, it may do just fine (you're not connecting to any consumer-grade gear, so the loading may be suitable). If the 50-cent fix doesn't work, then you can go for the $50 fix

It might be more useful if we knew exactly what you're trying to do with the signal. Are you simply feeding each camera to two inputs, the DVR and something else? Or does each camera need to go to multiple destinations? Do you need to do this with ALL the cameras, just one, or just a few?

Is there a compression/quality setting you can change?

You can, and it will.... how bad will depend on a number of factors. Right off, you're cutting the signal level in half, so the picture will get a little darker. If whatever you're connecting to the other side of the Tee doesn't put a proper load on the line, it could get VERY dark and lose a lot of contrast. Best way to do it is with active line splitters, but it won't hurt to simply test it first with some Tees.

GEM also has one that does power and ethernet over a coax line: http://gemelec.com/index.php?page=shop.product_details&flypage=shop.flypage&product_id=704&category_id=68&manufacturer_id=0&option=com_virtuemart&Itemid=1

Not all AC waveforms are sinusoidal.

Sorry, poorly worded... "AC-like" is what I was going for, since a video signal LOOKS like an AC waveform.

You SHOULD feel dumb! It takes me at least four glasses to become that forgetful!

I can't speak SPECIFICALLY for the VBM model (we've always used the VCM variant), but I should think so. Consider that it otherwise would require separate power and BNC connections, there should be LOTS of room for an RJ45 (or however it terminates; I've never used the version with the built-in balun). Those are the maximum resolutions you'll get with any analog system, so no, it's not "over-buying". Keep in mind that even if it were, you may want/need to upgrade the DVR some day, so there's no point in under-spec'ing the cameras now. Something like this? Most brands (GEM, GVI, MuxLab, NVT, etc.) have similar models...

Have you looked at using a NAS array with supported IP cameras and encoders? Check the likes of QNAP and Synology - many of their systems support direct writing by IP cameras, with management via web interface. QNAP, I know for sure, has versions of most of their models that are designed specifically for surveillance use; I believe Synology does as well, and AFAIK both are based on a form of Linux/BSD/*nix. For analog cameras, you'd just need to use a supported encoder. Both have demos available on their webstites.

Looking through other recent threads, I looked at this CNB camera ( VBM-24VF ) http://cnbusa.com/en/html/product/product.php?inc=spe&seqx_prod=1077#p_v1 I like it's variable focal length - would let us dial-in just how wide of a view we need. One thing that's not clear to me is just what angle it can point to... Could I mount it with the dome pointing perpendicular to the wall? And have the camera's view skimming the wall? Those are fantastic cameras, and yes, you can mount them to the wall - you can aim them pretty much anywhere within a full hemisphere, including looking straight back down the wall. That's an option on some models - without it, you can still use UTP, but you need to use a separate video balun. Not difficult to do, although either way, you WILL need a balun to connect the UTP to the DVR. This does bring up one point though: while the Lorex cameras are powered by the DVR through their proprietary cables, you will need to supply power to any other cameras yourself. The CNBs are dual-voltage, meaning they'll work with 12VDC or 24VAC (or just about anything in between, although those two are the "standards" in CCTV). It appears on most of the specs - for example on the CNB above it says: Video Output Level 1.0 Vp-p (75Ω, Composite) That just means the AC video signal measures 1V peak-to-peak, which is really pretty much universal for analog video (they specify p-p because AC voltage is most commonly rated and measured at its RMS (root-mean-square) level).

Best cameras *for the money* right now are probably the CNB Mona Lisa line. 600TVL, outstanding low-light capability, true day/night, no IR needed in most cases. You won't find them for $20, though. Don't expect much of anything for a measly $20. You think your cheap cameras look "pixelated" now, wait until you compare them to *quality* cameras.