Re: CAN BUS in security ?

[kormesii <ilian.costov@xxxxxxxxx>]

On Dec 28, 12:16=A0am, nick markowitz <nmarkow...@xxxxxxxxx> wrote:
> On Dec 27, 12:41=A0pm, kormesii <ilian.cos...@xxxxxxxxx> wrote:
>
> > I wondering is there any panel that use CAN BUS for system bus ?
> > Obviously there are reasons that interface (CAN BUS) to not used in
> > security equipments ... Does anybody know why ?
>
> Panels must be able to pass UL listing if there being used for certain
> jobs and it is expensive to get this listing.
> panel manufacturers are reluctant to add =A0new technology because of
> the cost.involved unless it is really going to do something fantastic.

Yes expencies are good reason. BUT actually it's not so much...
However,
 most of Panels use the old good RS485 interface for system bus.
The problem is it's not intended for multi-master transfers. I.e. the
protocol
must be MASTER->SLAVE...
However as far as I know Paradox do it. How ? I don't exactly... :(
I think it's some kind of Time-Division scheme. But the real problem
occurs in
big systems where many devices must report/communicated each other,
for
example one IP (LAN and/or GSM communicators), and also audio and
video verification methods... in network with let say 8 KBD devices...
So, here
RS485 is quite useless... In such situation in my opinion multi-master
protocols
going to suite better, while RS485 will make many problems and finally
makes limited
functionality. So that's why I ask for CAN bus... However because I'm
very
interesting in that problem any advice or know-how of existing panels
will be very
helpfull for me...
Thanks in advance !