Document Home

Valid HTML 4.01 Transitional

Nokia N810 and 770 Internet Tablets

James F. Carter <>, 2006-03-24, updated 2008-03-15

There's a lot to criticize in our government's response to hurricane Katrina, but the complaint that most bothered me was that the various police, fire and military forces could not communicate and coordinate because their radios were all on different frequencies. What a joke! They should be using the Nokia 770's Bluetooth to work through a commercial cell phone and put data packets on the global Internet. It would be fair for emergency agencies to subsidize high availability features in the cell towers, such as big, fat battery backup.

Here is an imaginary ride in a police car illustrating several uses for a handheld device which are poorly served by present police communications equipment. In this story I'm not assuming the maximally wired city of the previous one; I'm trying to stick with components that I could demo today just by compiling and installing them on my 770.

Ooo, a pothole! And a Mini-Cooper is trapped in it.

Cut the Mini-Cooper jokes and just fill out the report. I'll stop on top of the thing so you can get a GPS reading.

The police are the eyes of the city, and the Department of Public Works can't repair the pothole unless the eyes report it. The cops will be instructed to bookmark the web form for requesting street repairs. The only thing here that isn't off the shelf is the local plug-in that queries (via Bluetooth) the GPS unit in the police car and fills in the coordinates on the web form. GPS to Nokia 770 by Bluetooth is standardly supported, but it will take a slight bit of work to get the result onto the form. Intelligently pre-filling other fields on the request form, and using listboxes where possible, will save the cop a lot of text entry, which is not the handheld device's strong point. (The N810 has its own GPS receiver, but even so, a car unit can have a better antenna and there's no worry about using up the battery.)

Do you think that guy is reacting to us? I'm going to check out his license plate... Stolen, carjacked! Just a few minutes ago.

Report it; request backup. He's turning onto Avalon; we'll nail him there. Lights and siren... Rabbit! But he won't shake this coyote...

Most of this is simple web forms and database access. But in a high-speed chase it's important for headquarters to keep track of where each car is. For an off-the-shelf demo I would use a N810 and write a script to periodically, once every few seconds, query the GPS daemon and transfer the car's location onto a web form, submitted to the headquarters server via Bluetooth to a commercial cellphone.

But for production use I would commission a car router, that is, a phone chipset and external antenna mounted in the car, with a wired GPS having a real antenna, optimized to talk to the two cops' handheld machines by Bluetooth and to send their packets to the cell phone tower and thence via the global Internet to headquarters, or wherever else is relevant to their mission.

More and more police departments are equipping their cars with video cameras to record what their officers are doing, so the officers can't be falsely accused of wrongdoing -- or when the officers do misbehave, so responsibility can be taken in a way that avoids reinforcing the client community's mistrust of cops. The camera orients on the officers using their radio signals. It could be a lifesaver if the video feed (aggressively compressed) went back to headquarters in real time.

There's something funny about that GM Suburban; I'm going to check his plates. Hmm, there's a federal tag on the record, report if you see this car. Following the link... OK, we see the car; here's our GPS. Quick response! A H.323 invitation icon.

Congratulations, you guys caught El SuburbaƱo del Muerte. BATF has been after these guys for months; they fly heavy weapons in from Mexico and sell them to the gangs here. You don't want to tangle with this one without serious armor plate. If you can kind of hang back but keep him in sight, two of our units are about ten minutes away from your position and can make the stop. Let's keep the H.323 connection open. Are you able to feed through your GPS?

Not on session, but if you have a position reporting form I can send a feed to that.

Here's the URL. Stick with him but not too obviously, and let us know what's happening. Our two units are on session.

Here's the real payoff: instant ad-hoc coordination with another agency, one that is obscure enough that coordination probably couldn't be prearranged.

I'm picking H.323 for the protocol not because I like it but because I know a little about it. An instant messaging protocol is a whole lot easier for firewalls to deal with, particularly for the originating end.

Instead of H.323 one could use VOIP. However, in this scenario you're coordinating the city cops, the two BATF units, and their headquarters, plus city headquarters would probably like to be invited. A conference call like this is a lot easier to set up on H.323 or instant messaging. Also, while VOIP can be recorded at headquarters, text messages make a much more sanitary permanent record.

Oops, we're heading into the twilight zone: bad cell phone coverage. But we're in luck: the neighbors have 802.11b and are letting us on.

The Nokia 770 can switch seamlessly between the cell phone and 802.11. Hypothetically the police could ask concerned citizens to allow them to borrow their broadband connections by programming a published access key. The crypto would have to be asymmetric, so the public key would be published but only those knowing the secret key could use the channel. This kind of authentication is vaporware, not part of 802.1x.

Los Angeles police cars are currently equipped with large, clunky computers that can communicate with headquarters, but I don't know what frequencies or protocols they use. It seems to me that the handheld PDA would be a lot easier to handle, and could also be taken from the car, for example to take a police report at the scene of a crime.

Document Home