[michael_mei]

I have an unusual application in mind that I would like comments on. I work at the Coast Guard where we have unmanned radio sites that have land based telephone lines that are seldom used since our technologists seldom need to visit them. Ideally we would like to replace those phone lines with a fixed wireless terminal (FWT) that provides an RJ-11 with dial-tone and an RJ-45 with Internet data that we would like to connect to a VPN router to connect to our internal operational IP network. A concern raised internally was the loss of e911 capability if we eliminate the analog phone lines. I've worked at a 911 equipment vendor so I knew that accurate location is possible with appropriate devices. While land lines furnish 911 PSAPs with a text address string, automatic location information (ALI), A-GPS equipped cellular devices can furnish very accurate coordinates to a 911 PSAP. I searched long and hard and could only find legacy CDMA based FWTs supporting accurate e911 location but none supporting GSM/HSPA/LTE. However I tested with my previous blackberry Torch 9800 (on Rogers, a GSM provider) and it provided very accurate e911 coordinates (dictated to me by the 911 PSAP, verified using google maps) so I assume and hope that this remains to be the case on the newer QNX (OS 10) based phones. Therefore I was thinking that maybe we could somehow have a blackberry in the building always connected to a charger (potentially issues if/when the battery dies?) connected to a Bluetooth cellular gateway to get regular dial-tone on an RJ-11 and connected somehow to an external antenna (if even wirelessly attached to the phone with a car holster but a direct physical antenna connection would be ideal but then might there be lightning issues?) and use the Blackberry without a BES connection with a VPN router (connected to the BB by WiFi). While the application is non-critical (we could drive to the site as we currently do if the remote access solution, of which this would be a part, failed), I wonder if the cellular modem in Blackberries were generally designed/are able to handle a small amount of background VPN keep-alive traffic 24x7x365. Or might there be other reasons why we should not use the cellular modems in an application like this? If not we could buy industrial grade cellular modems and keep the phone lines. However the fixed monthly fee for cellular voice for us is very attractive such that we could probably obtain cellular voice and data for a similar cost to that of our land phone lines so we would prefer this while retaining accurate e911 location on the phone line. Comments and suggestions welcome.

[Dunt Dunt Dunt]

I have an unusual application in mind that I would like comments on. I work at the Coast Guard where we have unmanned radio sites that have land based telephone lines that are seldom used since our technologists seldom need to visit them. Ideally we would like to replace those phone lines with a fixed wireless terminal (FWT) that provides an RJ-11 with dial-tone and an RJ-45 with Internet data that we would like to connect to a VPN router to connect to our internal operational IP network. A concern raised internally was the loss of e911 capability if we eliminate the analog phone lines. I've worked at a 911 equipment vendor so I knew that accurate location is possible with appropriate devices. While land lines furnish 911 PSAPs with a text address string, automatic location information (ALI), A-GPS equipped cellular devices can furnish very accurate coordinates to a 911 PSAP. I searched long and hard and could only find legacy CDMA based FWTs supporting accurate e911 location but none supporting GSM/HSPA/LTE. However I tested with my previous blackberry Torch 9800 (on Rogers, a GSM provider) and it provided very accurate e911 coordinates (dictated to me by the 911 PSAP, verified using google maps) so I assume and hope that this remains to be the case on the newer QNX (OS 10) based phones. Therefore I was thinking that maybe we could somehow have a blackberry in the building always connected to a charger (potentially issues if/when the battery dies?) connected to a Bluetooth cellular gateway to get regular dial-tone on an RJ-11 and connected somehow to an external antenna (if even wirelessly attached to the phone with a car holster but a direct physical antenna connection would be ideal but then might there be lightning issues?) and use the Blackberry without a BES connection with a VPN router (connected to the BB by WiFi). While the application is non-critical (we could drive to the site as we currently do if the remote access solution, of which this would be a part, failed), I wonder if the cellular modem in Blackberries were generally designed/are able to handle a small amount of background VPN keep-alive traffic 24x7x365. Or might there be other reasons why we should not use the cellular modems in an application like this? If not we could buy industrial grade cellular modems and keep the phone lines. However the fixed monthly fee for cellular voice for us is very attractive such that we could probably obtain cellular voice and data for a similar cost to that of our land phone lines so we would prefer this while retaining accurate e911 location on the phone line. Comments and suggestions welcome.

And why are you getting rid of the land lines?

Why is e911 so important at a unmanned site... won't technicians all have their own mobile devices?

I think if you called your corporate contact with you Service Provider, they might be able to offer you a Wireless Network Router that is designed for this. We were using a Verizon Wireless Mi-Fi Router that did e911 and had both phone and data connections.

[michael_mei]

While we seldom visit these unmanned locations and will probably need to do so even less often with a good remote access data solution, our staff does not want to lose the e911 capability that the land lines offer. The land lines have been there for years, from before technicians had cellular phones. Our shelters are often fabricated of metal so a hand-held cellular device often doesn't work in the building. So while they should seldom need it, a cellular device with voice and data with an external antenna should give us what we need. While we can retain the land lines, they are very seldom used and our contract pricing for cellular voice and data is very attractive.

I did contact the sales team at our wireless provider about FWTs with e911 for their GSM/HSPA/LTE network but they did not have anything with such support and I had a very difficult time trying to find a product with such support. At one point I found a Verizon device that was CDMA with e911 but thanks to your post I checked their web site again and I will now investigate whether or not the Novatel 4G LTE Broadband Router with Voice (T1114) will meet our needs.Its datasheet online suggests that it supports CDMA1xRTT and LTE and A-GPS for e911. Hopefully it supports A-GPS for e911 on LTE as our provider does not support CDMA. Also hopefully it can be purchased unlocked to work in Canada.

[michael_mei]

Sadly an unlocked version of the T1114 is not available.

We can try to see if a combination of a cellular repeater and a GPS repeater at each of our sites will allow employees with their existing phones to get good e911 coordinates. Using a VoIP provider that supports e911 is another, less preferred, option. Other than my original suggestion to try to hack a smartphone like a Blackberry to be like a FWT, I'm out of ideas. It appears that FWTs supporting A-GPS e911 location and the GSM family of protocols are simply not available on the market. It must be possible to produce such a product since my old BB Torch 9800, a GSM/HSPA device, supported it.

[DrBoomBotz]

Sadly an unlocked version of the T1114 is not available.

We can try to see if a combination of a cellular repeater and a GPS repeater at each of our sites will allow employees with their existing phones to get good e911 coordinates. Using a VoIP provider that supports e911 is another, less preferred, option. Other than my original suggestion to try to hack a smartphone like a Blackberry to be like a FWT, I'm out of ideas. It appears that FWTs supporting A-GPS e911 location and the GSM family of protocols are simply not available on the market. It must be possible to produce such a product since my old BB Torch 9800, a GSM/HSPA device, supported it.

Get a an ATA(analog telephone adapter) you can get e911 service over sip.
I don't see why this is less preferred.

[michael_mei]

The had thought of that option and we may well do that. Given my experience with VoIP over cable Internet at home (it's often good, sometimes not), I have some concerns about what the quality of VoIP over cellular Internet may be even though this service will probably seldom be used. I strongly suspect that the audio quality on cellular voice will be cleaner and better in general (and immune to congestion on the Internet). Also, in our case, the monthly cost to maintain cellular voice service plus the cost of cellular voice minutes is about the same or less than we'll be able to get with a VoIP provider but the cost is negligible in either case.

[michael_mei]

Also, while not a big deal, the e911 service with at least one SIP provider (mine at home) is that the service is not as good because your call goes to a sort of VoIP PSAP and then they call and bridge in the real PSAP and dictate the person's location. Maybe some VoIP service providers offer e911 direct to the appropriate PSAP but I'm a bit doubtful. One would need to test since that level of detail would not be easily available when researching VoIP providers.

In general there have been media events pertaining to issues with 911 on VoIP.

It's definitely an option to consider, just not the preferred one IMHO.

[DrBoomBotz]

The had thought of that option and we may well do that. Given my experience with VoIP over cable Internet at home (it's often good, sometimes not), I have some concerns about what the quality of VoIP over cellular Internet may be even though this service will probably seldom be used. I strongly suspect that the audio quality on cellular voice will be cleaner and better in general (and immune to congestion on the Internet). Also, in our case, the monthly cost to maintain cellular voice service plus the cost of cellular voice minutes is about the same or less than we'll be able to get with a VoIP provider but the cost is negligible in either case.

I have been deploying mobile VoIP over cellular data for >2 years and it works "fine".
One thing I noticed from my testing is that cellular voice was not as good as I expected it would be.

In a static set-up VoIP over cellular should be pretty deterministic.
I suggest a pilot test, you may be surprised.

Have you got reliable power at these radio huts?

BTW thanks for the tip about PSAP bridging.

[DrBoomBotz]

I have been deploying mobile VoIP over cellular data for >2 years and it works "fine".
One thing I noticed from my testing is that cellular voice was not as good as I expected it would be.

In a static set-up VoIP over cellular should be pretty deterministic.
I suggest a pilot test, you may be surprised.

Have you got reliable power at these radio huts?

BTW thanks for the tip about PSAP bridging.

Ok just had my coffee.
Of course you have reliable power.

[michael_mei]

Indeed we have reliable power.

I worked for a 911 equipment vendor in a past life. One advantage of having the call go direct to the correct PSAP using the standard legacy mechanisms (long story omitted) is that the operator will see, in the case of a land-line call, text showing your address in what is called automatic location information (ALI) that cannot be blocked by the caller. For a cell phone call they will get coordinates and generally with another system a display on a map showing where you are (also with land-line calls). They won't know if the coordinates for cell phone calls are accurate though and the coordinates won't be accurate for a FWT that doesn't support A-GPS e911. I learned this when testing a unit advertised as having this support but it turned out not to. There was a documentation error, a cut-and-paste from one of their CDMA based products they had that did support A-GPS e911.

Anyway, with the "intermediary" call centre involved with nomadic VoIP service in my experience, the operator will be told your location (whatever you typed into the VoIP provider's web portal) so the automated mapping tool showing your location won't be available to real PSAP. Obviously being able to view the location is better than having heard it once on a bridged call.

Thanks for noting your good experience with VoIP over cellular data, if we do decide to take that road.

[DrBoomBotz]

What would the 911 information for the land-line of typical radio hut look like?

In rural Ontario(from memory) the responders get a lot and concession number.
I once saw a police car go whailing past the address and come whailing back some minutes later.
A comments field that said "Look for the flashing light on-top of the 800' radio mast" would help considerably in this regard.

[michael_mei]

Certainly a lot and concession number would be of little practical value to responders.

We have many locations, some more rural than others. I have no idea how good the ALI information is in the individual cases although. If we wanted to we could do test calls from each location to find out (as a courtesy one calls on the non-911 line first to ask if one can do a test 911 call). Coordinates from a A-GPS e911 enabled cellular device could well represent an improvement for us!