VOIP for Nine Year Olds

How easy is it to set up VOIP over Wifi? One of my goals is to help people in the developing world get telephony. The problem is that the target market (e.g. some guy in a village) may not be a highly skilled geek who can handle Linux, Wifi, and Asterisk configuration.

Imagine a simple “VOIP in a box” kit that comes pre-configured so that (almost) anyone can set up a VOIP over Wifi link. To test this concept I borrowed a Ubiquiti NanoStation 2 (NS2) and configured it to talk to my roof top Air-Stream node. I then connected an IP04 IP-PBX to the NS2 and rigged up a small 12V/1.2AH battery to power the system (good for a few hours, enough for my tests). I connected a standard analog phone to one of the IP04’s 4 analog ports.

My first test was to hop on my bike and peddle about 4km to a nearby hill. On this hill I fired up the system on a park bench. I pointed the NS2 by hand roughly in the direction of my house, and managed to call my home OK. I was very happy was this as the antennas of both the NS2 and my roof-top node were quite low gain, and the alignment was pretty rough. I used a hill as carrying a mast on my bike would have been tricky! So this test showed that useful ranges were possible using the NS2/IP04 combination, with a minimum of alignment and fuss.

OK, so now I needed some test subjects to see if anyone could set the system up. Fortunately I have a ready supply of kids. Twelve year old Amy and nine year old William were drafted for the task. So after school I dragged them away from the cartoons (William) and MSN chat (Amy) and spent 5 minutes showing them how to connect the VOIP over Wifi system together. Some key points:

  1. Plug power into both the NS2 and the IP04.
  2. When the NS2 signal strength LEDs light up it is ready.
  3. When you get dial tone in the analog phone it is ready.
  4. Point the NS2 at our house.
  5. Then dial 2001 (which routes the phone call to another IP04 in my house).

Then I put all the bits in a cardboard box and told them to head down to the park, set it up, and call me. They headed out the door, yelling at each other and fighting as per usual. Your typical junior phone company executives. By a not-very democratic process it was decided that William would do the set up while Amy took the photos.

So we plug in power to the NS2:

Then the IP04:

Then point the NS2 in the general direction of our house, wait for all the lights and dial tone!

I waited anxiously in my home office, wondering if it would all work. Just as I was about to give up and head to the park to find out what went wrong, the phone rings.

HI DADDY!!!!!!

Bloody hell, that was loud! My ears are still ringing. No one can scream into a phone like these kids. It also reminded me that maybe I needed to lower the volume of the phone ports a little!

Possible Applications

  1. Two of these systems could be used to make a point-point link over 5-10 km, enabling 4 telephone calls between any two sites.
  2. The combination of the IP04 and NS2 drew less than 400mA at 12V (4.8W), so a small solar panel could power the entire system. This means it can be deployed anywhere, independent of mains electricity. Think disaster relief, remote locations, 3rd world countries.
  3. One of the IP04s could be configured with FXO ports, and connected to several telephone lines (rather than telephones). So the point-point link could be used to extend the regular phone network 5-10km to a remote location without telephone lines.
  4. Add a billing system to IP04 (it runs uClinux, sqlite, even PHP) and you have a micro-business for someone in a village selling phone calls.
  5. The NS2’s can be mesh-networked to build out an extensive, community-owned network.

Why IP04?

Why not use a SIP phone or ATA directly connected to the NS2? Well this may be fine for many applications. However the IP04 has several advantages.

  1. It’s open. Really open. Like hardware and software. What if the firmware on your ATA has an annoying bug? Too bad. What if the phone manufacturer decides to stop manufacturing your favorite SIP phone just as you are building out your network or need a spare? Too bad. With the IP04 you have the same sort of control over the hardware as you have with open software.
  2. The IP04 powers analog phones, unlike SIP phones that need their own power supply. Critical in a developing world application, where electricity is not widely available. Twisted pair is a lot cheaper to run than Ethernet cable, too.
  3. The IP04 has been carefully optimised to use just 3W at idle – about the same as a single SIP phone or ATA. This means the power system (e.g. solar panel and batteries) can be much smaller and cheaper.
  4. The IP04 runs Linux and Asterisk – so you have a wide range of configuration and switching options. It’s a PBX and Linux box, not just a phone.
  5. Hybrid solution using the IP04 and ATAs or SIP phones are also possible – just register the ATA/SIP phones with the IP04 as extra extensions.
  6. It’s a community designed, developed, and maintained product – which makes it ideal for community applications!

Why VOIP over Wifi?

  1. Why not use a cell phone? Well a cell phone requires an expensive tower to work. You may not have a cell tower handy, or it may not work, or it may be owned by a carrier who charges high costs for the use of “their” network.
  2. Or the cell network may have been wiped out in a disaster situation (cell networks require land line and electricity infrastructure).
  3. Using VOIP over Wifi communities (e.g. a village, hospital or university) can build up their own network at modest cost. They own and control the network. Free phone calls for ever.

9 thoughts on “VOIP for Nine Year Olds”

  1. I’ve been reading this blog since you were just finishing up the hardware building. I love what you’ve been doing and all of these neat off-the-wall applications for it. I’m getting my Ham radio license this weekend so the concept of using it for disaster infrastructure recovery is especially appealing.

    An experiment I’d like to see is the ad-hoc concept. Give each kid their own set of equipment and have them head off in opposite directions until they can’t make contact with each other.

    Kenneth (Middle of the Silicon Valley, CA, USA)

  2. Hi Kenneth,

    Thanks for your post and the kind words about the blog. You know I just re-licensed myself as a Ham (VK5DGR), after a break of a few years. I am looking forward to getting back on the air, and am thinking about working on some low cost software defined radio.

    You experiment is a good idea – it’s exactly the sort of thing I used to do as a kid with CB and walkie-talkies!



  3. David,

    That is absolutely brilliant! That is exactly how easy it should be to use! Of course this may not be a fair representation since if you are anything to go by, your kids are probably polymaths. :-)


  4. Brilliant is a good word. I’ve been reading your blog for a while now, and this post is the best. I like that you’ve open-sourced the hardware as well as the software. Ease of use is always good too! If a nine year old can figure it out, maybe I can too!


  5. That is Wonderful. I just had what I was looking for a long time.
    I will integrate it into one of my projects.


  6. I am just wandering how your project could be applied here in Brasil. That are a lot of communities that would benefit from this communication infrastructure.
    Very good work you have done.

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