Re: found some good deals ......

["Doug" <doug@xxxxxxx>]

"Chuck" <charlesmorris@xxxxxxxxxxxx> wrote in message
news:ikurhe$a5d$1@xxxxxxxxxxxxxxxxxxxx
>I found a few good deals and they are in the mail:
>
> 1) Speco HT650PT10X High Resolution Motorized Dome Camera
>
> 2) Speco DVR4TL250 4 Channel DVR
>
>
>
> Now a few questions please -- the DVR has BNC camera inputs but the
> instructions for the camera are a little more complex:
>
>
> ------------
>
> Connect the camera using the supplied terminal block:
>
> A) Connect the control unit via the twisted, 2-conductor line (max length
> length 1200 meters) to the pin array 5 (RS485A) and 6 (RS485B).  Connect
> all
> cameras in parallel to this 2 conductor control line.
>
>
> B) Feed the video signal at contact 3 via a shielded cable to the video
> input of the following unit (eg, monitor, camera switcher, video splitter)
>
> Connect the shield to contact 4.
>
>
> C) 12V + to pin 1 and ground to pin 2.
>
>
> -----------
>
>
>
> Ok now ..... RS485 control signals interface at a terminal block on both
> the
> camera and DVR.  What is the best twisted wire pair to use for this?
> Would
> one twisted pair of a Cat 5 cable work ok for 100 yards?
>
> If Cat 5 cable is used for the RS485 control signals, can I transmit the
> video and "shield" down a second twisted pair in the same Cat 5 cable?
>
> Could I ship 12 volts and ground down a third twisted pair in the same
> cable?  If so, how far?
>
>
> Last problem, the DVR has BNC connectors for video in.  Would I just
> soldier
> a BNC connector on the video cable for connection at the DVR?  What about
> impedance matching?  Any problems to watch for?  What am I missing?
>
> Thanks.
>
>

If you are using twisted pair for the video you should also use video
baluns.

Doug