Re: Sole Path ???

[nick markowitz <nmarkowitz@xxxxxxxxx>]

On Feb 7, 5:53=A0pm, jewellfish <jewellf...@xxxxxxxxx> wrote:
> 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 rep=
s for
> > Telular. =A0He was all excited that they have a communicator suitable f=
or sole
> > communication for commercial fire. =A0I listened to him and read some o=
f 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. =
=A0Big
> > whoop. =A0Its still a single communication path. =A0Now if it incorpora=
ted 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=
 was
> > 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 tru=
e?
> > 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. =A0If I
> understand NFPA 72, chapter 9 it does not mandate two communications
> paths for all methods of signal transmission. =A0This 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. =A0For instance, in the Chicagoland area many
> municipalities have direct connect (reverse polarity) connections.
> Signals over one set of conductors. =A0AES radios are taking the place
> of these hard-wired connections but, again, they are a single radio
> transmitter using a private network. =A0The 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
Way it was described to me
Tellular sends a fault to central if its servers do not see a check in
after so many minutes from unit so it is supervised .
that plus UL has lowered the requirements  realizing dual paths really
mean nothing in digital age if one phone line goes down all will. on
most telco systems these days