Re: Coax as data cable

["Roland Moore" <roland@xxxxxxxxxxxx>]

"G. Morgan" <alarmpro@xxxxxxxxxxx> wrote in message
news:1ni6p25ighuv1l9igo341hoduk064kvd0k@xxxxxxxxxx
> On Wed, 27 Dec 2006 20:40:50 -0500, "Robert L Bass" <sales @ comcast +
> net> wrote:
>
>
> 1.
>>Numerous professional installations still emoploy screw-on BNC connectors
>>for CCTV.  They work fine for composite video only but they're not good
>>enough for hi-def and some up-the-coax data applications.
>

I my opinion if you can't make a decent 2 or 3 piece crimp on BNC connection
in your sleep your not a professional in the CCTV world period. Using a
screw on for an emergency repair when your out of ALL other resources is
okay for a temporary fix. To any and all who have been in the business for
decades, or says they have been, then everyone should have thousands of
crimp on BNC connections under their belt, if for no other reason than
fixing all the twist on crap out there growing beards when the tape falls
off.
> 2.
>>As mentioned above, up-the-coax PTZ control data is an option.
>
Bilinx, Panasonic up the coax, Pelco up the coax etc are not interchangable.
In this case the Samsung/GVI PTZ doesn't support bilinx (and probably not
Biphase either).
> 3.
>>If it's a lengthy cable run your customer might be happier if you first
>>consider sending the PTZ via that extra coax.  It works well when properly
>>set up and it can be a time saver for you.
>
> BWAHAHAHAHAHA!!!!!!!

I believe you'd run out of video signal on RG-59 or RG-6 run long before
you'd run out of control signal on a 485 data run. If the turd doing the
original installation had not used coax at all, and just the correct data
cable instead, I could have used twisted sender and 485.
>I don't know what the heck that second coax is for

I have no idea either. That's why I posted just to see if there was
something I missed.
I have seen guys do strange things like terminate all coax with F connectors
and then use an adapter to BNC connectors because they say it gives better
signal strength, even when you show them on a meter the extra dB loss, they
still persist.

> Wow...  You never have even *SEEN* a CCTV system apparently.  Screw-on
> BNC's huh?  LOL....
>
>
> The only viable data over coax I've seen is Pelco's 'Coaxatron' <sp>
> protocol which requires Pelco products on each end.   I suppose one
> could also use third party modems on each side to transmit rs485 data,
> but that would be cost prohibitive compared to just running a Cat5
> with the coax -- even then only one cable is needed for data and
> video, so I don't know what the heck that second coax is for.
>
>
> I hope the 2 hour phone course CCTV 101 is not offered in your
> distance learning catalog.
>
> --
>
> -Graham
>
> (delete the double e's to email)