911 from remote site

Unanswered Question
Feb 5th, 2009

Hi all,

I have a difficult situation that I am not sure how to handle.

We have a branch location that is connected via a 2821 to the campus over MPLS. there is a voice T on site (for local calling). They have recently acquired another building that we have extended service to. This "extension of service" is being accomplished by 1.2 GHz microwave dish. For all intense purposes, this is a fiber run (terminates as fiber on both sides).

The trouble comes in when we are talking about 911. This new building has a seperate physical address. Because of this, we need calls to 911 to have this address in their ALI. We have talked to the Telco, and they cannot distinguish this new set of DID's as belonging to that address (the address is listed as the point of demarcation, which is the original building -at the other address). Our only option is a POTS line at this address (which would satisfy the ALI requirement). This would, in effect, be a CAMA trunk.

How is this accomplished? Is there a media converter that can digitize an analog signal so that it can ride the dish back to the main campus to terminate in an FXO Port? If not, what are the options? I have thought about treating this as a seperate site (installing a router and using the Microwave as a shared t, then terminating the FX0 into that). We have thought about just putting a analog phone on the wall (not the greatest solution). Another posibility was an ATA with X extension. When 911 is dialed (from the device pool for that building) a route pattern or translation pattern is matched that converts it to the extension of the ATA. The ATA rings and this other device (which we need to acquire) auto answers, then forwards to the POTS line (which would be on line 2 of that device). (not sure if it would work.

any help would be greatly appreciated.

-Ronnie

I have this problem too.
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kelvin.blair Thu, 02/05/2009 - 13:14

Ronnie,

In this case you would use either ERS or place another router like a 1861 onsite that will terminate a single POTS line. You didn't mention the type of PBX. If you have call manager, you can configure this gateway as an h323/mgcp and if call manager can talk directly to this router then you can add it just like you would do in a normal branch/voip situation.

Ronald Spencer Thu, 02/05/2009 - 13:40

Hi Kelvin,

Thank you for your response. we were thinking a router to terminate the POTS line as well, but weren't sure it was the right way to handle this issue. If we have a router, should we consider getting a SRST enabled router and having the phones register with it. That way if the Dish is down, they would still have phones (currently they would not). would this terribly convolute the situation (given that the PC's connect through the phones and would have to route through this router?

kelvin.blair Thu, 02/05/2009 - 13:46

An SRST/CME enabled router is the best route to go. As we all know Dish is not very stable and you will have outages. If you do this, it might be best to install more then one POTS. If one is enough during the outage then that is fine. My personal preference would be a min of two with a preferred preference of 3 or more. This way you can at least continue to function. As for convolute the situation, No I would not think so. Your at least giving them Phones in case dish failure and 911.

Ronald Spencer Thu, 02/05/2009 - 13:50

Oh, the solution would not convolute the routing because we could use this router simply as a SRST (providing no routing for data traffic). In other words, we would list the IP of this router as the 4th CCM in the phone so that they would contact it when they could not contact the 2 call managers or the MGCP Gateway at the other building?

kelvin.blair Thu, 02/05/2009 - 13:52

You would list it as the SRST gateway in CM and yes everything else is correct.

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