[cisco-voip] Cisco VOIP and fire alarm phone lines

[Nick Matthews]

The three most common problems with fire alarms are this:

1) DTMF.  A few of the signaling methods use very precise and rapid
DTMF to communicate.  This rapid method requires timing between the
digits and for the length of the DTMF must be preserved.  This means
you can't use DTMF relay.  This means you need to use SIP or H323 with
no dtmf-relay configured.  MGCP/SCCP does not have the option to
disable dtmf-relay, and they're generally the protocol in use when
these problems arise.

2.  Modems.  Some of them do modem communication to communicate, and
you need to treat them like fax ports, and make sure modem passthrough
is configured correctly.

3.  Voltage problems.  A lot of these devices were designed a long
time ago when the average voltage supplied by an FXS port was much
higher.  Voltage has been reduced around the board, especially with
VOIP devices that are on the FXS side.  The VIC3-FXS has some
sub-models that allow for higher voltage and interop with older
devices.  As well, there are 3rd party devices (like Viking I believe)
that offer some voltage assistance on these devices.


-nick

On Wed, Nov 4, 2009 at 3:10 PM, Fuermann, Jason <JBF005 at shsu.edu> wrote:
> The common two modes,
>
> Contact ID: uses hook switching to communicate
>
> 4+2 or 4x2: uses touch tone to communicate
>
> Had to put a butt set on it to figure out why it wasn’t working
>
>
>
> We have 4+2 working on our campus using VG224’s running SCCP. The fire alarm
> guys get comm. failures and blame voip, but it has always been a pair
> problem on the copper. That being said, we are switching over to IP DACs
> because they are more reliable (monitored every 60 seconds for availability,
> and redundant from the closet instead of a copper pairs across campus on the
> same cable, through the same splices).
>
>
>
> From: cisco-voip-bounces at puck.nether.net
> [mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Lelio Fulgenzi
> Sent: Wednesday, November 04, 2009 1:55 PM
> To: Tim Reimers
> Cc: cisco-voip at puck.nether.net
> Subject: Re: [cisco-voip] Cisco VOIP and fire alarm phone lines
>
>
>
> There was some talk about this a while back and my research (mainly from the
> archives and contacting individuals) shows two things:
>
> it depends on the protocol you are using (SCCP, MGCP, H323), and
> it depends on the protocol/functions of the alarms
>
> If you are using simple alarms, that simply call home with no active data,
> then SCCP should be fine.
>
> If you are using intelligent alarms, those that supply contact info for
> example, then I believe you have to go with H323.
>
> If you do some searching on the archives, you'll get some threads you can
> look through.
>
>
>
> Lelio Fulgenzi, B.A.
> Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1
> (519) 824-4120 x56354 (519) 767-1060 FAX (JNHN)
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> "Bad grammar makes me [sic]" - Tshirt
>
>
> ----- Original Message -----
> From: "Tim Reimers" <treimers at ashevillenc.gov>
> To: cisco-voip at puck.nether.net
> Sent: Wednesday, November 4, 2009 2:51:54 PM GMT -05:00 US/Canada Eastern
> Subject: [cisco-voip] Cisco VOIP and fire alarm phone lines
>
> Does anyone know if Cisco has any recommendations they officially make on
> supporting analog telephony devices like fire alarm panels?
>
>
>
> We use ATAs for supplying dialtone to  fire alarm dialers, and we're getting
> issues with some panels getting "comm trouble" issues, and data not getting
> to the monitoring company correctly.
>
>
>
> The security vendors and the OEM manufacturers are saying "we don't
> recommend VOIP for alarm lines"
>
>
>
> Our management is saying that surely Cisco supports this, and with the
> correct configuration, they can make this happen.
>
>
>
> I'm looking for some official Cisco guidance (links to design guide
> statements, etc)
>
> that might break the deadlock, and either allow me to prove to the vendors
> and OEMs that VOIP is indeed a stable technology
>
> or, allow Cisco the graceful way of saying "it's best not to do that"
>
>
>
> Anyone got anything to offer?
>
>
>
> I'd imagine that there's a fair number of folks who've just decided not to
> use VOIP for this purpose-
>
> That's just not the decision here though..and I'm not the policymaker on
> that level.
>
>
>
> Tim
>
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