Re: Sole Path ???

[jewellfish <jewellfish@xxxxxxxxx>]

On Feb 7, 2:18=A0pm, "Bob La Londe" <n...@xxxxxxx> wrote:
> I received a phone call and an e-mail the other day from one of the reps =
for
> Telular. =A0He was all excited that they have a communicator suitable for=
 sole
> communication for commercial fire. =A0I listened to him and read some of =
the
> info he e-mailed to me and it just doesn't add up.
>
> It looks like a GSM communicator sending two signals instead of one. =A0B=
ig
> whoop. =A0Its still a single communication path. =A0Now if it incorporate=
d a GSM
> and a CDMA communicator with a trouble output if either fails to test I
> might buy into it, but it sure doesn't look that way when giving it the
> quick once over. =A0Instead they seem to indicate the the NFPA standard w=
as
> changed???
>
> Really? =A0All these years that we have been required to provide two
> communication paths, and now NFPA says we only need one? =A0Is this true?
> What am I missing?
>
> Esplain it to me Rucy.

Bob,

I am most familiar with the 2002 & 2007 editions of the code as most
locations I deal with have not adopted the 2010 version of NFPA yet
and so the following refers to these versions of the code.  If I
understand NFPA 72, chapter 9 it does not mandate two communications
paths for all methods of signal transmission.  This chapter breaks
down into sections dealing with different transmission technologies.
Now, when systems use DACTs, then yes the code specifies that that
primary method must be a phone line and the secondary path can be a
phone line or several other alternates methods ( one of which is
cellular phone, which Tellular models are designed to fulfill).
However, other sections that deal with other technologies do not
mandate multiple paths.  For instance, in the Chicagoland area many
municipalities have direct connect (reverse polarity) connections.
Signals over one set of conductors.  AES radios are taking the place
of these hard-wired connections but, again, they are a single radio
transmitter using a private network.  The Tellular TG-7fs literature
seems to indicate that it is using standard cellular networks, so
there must be some change in the code to allow for this.

Regards,

Bill