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VoIP, SIP registration, and timeouts

2013-05-08 , , , Comment

Quick comment… Everyone in the family has multiple devices— phones, tablets, game consoles, computers— and these tend to make network connections that linger. If you have a firewall like I do, the default TCP and UDP timeouts are probably too high (often 3600 seconds) and when everyone is around on the weekend you get poor performance and strange complaints about how things don’t work. Separately, I have an OBI100 VoIP device providing phone to the house. The OBI100 has a default SIP registration period of 60 seconds and re-registers after half the interval, this is a bit too frequent so I have mine set to 300 seconds. As I’ve found, if the firewall expires the connection quickly you can end up with what looks like a valid registration at the SIP provider and can make outgoing calls but incoming calls fail. I’ve worked around it by expiring connections at 360 seconds for TCP and 180 seconds for UDP.


Ruby debugger in 1.9.3

2013-04-03 , , , Comment

I decided to really dig into Ruby and its ecosystem. It’s quick to get things started using RVM and the language is fun (and for what it’s worth, on my system Ruby 1.9.3 is slightly faster than Perl 5.12 on my favorite trivial string parsing test of extracting fields from 500,000 lines of Apache combined log) but coming from Python and Perl I find frustrating quirks in the tools. Today’s example is that the debugger is broken on 1.9.x and searching turns up hundreds of “fixes” that don’t work or only build for specific releases of ruby and the dependencies. I realize it isn’t “core”— there is a debug module in the 1.9.3 stdlib that is kind of undocumented— but it is the sort of thing you expect to work or get flagged as broken. It seems that the authors/maintainers of the debugger gave up on it, but Gabriel Horner has a fork that works.


Switching to VoIP with the OBi100

2012-07-15 , , , Comment

We’ve had telephone service through the local cable company for the past four years in a digital tv-phone-internet package. The “digital voice” service from Time Warner is voice-over-DOCIS but otherwise unexceptional and runs on the same cable network as the TV and internet services. We’ve seen our monthly price of the package climbing up and annual offers to new customers for the same package sliding down and received very little satisfaction from customer service. The whole bundle costs too much for the value we get. Cutting cable is a topic for the future, but I think I can do better for our very modest home phone usage.

I bought an Obihai OBi100 VoIP device. A colleague raved about how great his was and I found it selling new for less than $50 with tax and shipping. The first thing that struck me was how tiny it is, pictured here with a pack of gum and a pen for comparison:
OBI100 size
The device is about the size of a deck of playing cards, but a bit thicker. The second thing to know is that once it picks up an IP address with DHCP, the web-based interface offers both a “wizard” guided setup and a do-it-yourself mode where you input the configuration. I spent an hour reading the PDF documentation and forums on the vendor site, fiddling with Google two-step authentication, setting QoS on my router, and flashing the device with the most recent firmware before setting it up. The “wizard” is, at least for me, easier and I had the device working perfectly inbound and outbound as line #2 on my desk phone with Google Voice in five minutes.

My next step is to select a SIP provider and configure it as a second service.


Comments on Android on HP Touchpad

2012-07-14 , , , Comments

It’s been months since I modded my HP Touchpad with Cyanogenmod. I’m not going to get into how to do it because there are fairly adequate guides. I’m now running a mid-June official CM9 nightly build. The touchpad is a nice Android tablet (read that “games”) and a great e-reader (kindle & nook apps) after setting the DPI to the native 132 with DPI Changer. The wireless behaves itself, battery life is acceptable, and other than the camera and app store it mostly works. The camera is only supported by a binary blob in an old kernel unless HP makes a code drop, so may never work. The Google app store, a.k.a. Google Play, is annoying in that it checks the DPI and make and model of the unit when it is first run but never again after that and disables updates on many existing apps. Setting a few values (youtube example on CM7) in the build.prop then clearing the app cache in system settings, clearing the /cache partition, and rebooting with the default DPI fixes it. I used


which gives better results than the usual recommendation of faking a SGH-T989. After updates, I switch the DPI back to 132.


Odd scam email from

2012-06-27 , , , Comment

Received an odd email reads like some kind of link scam. That it came through the forwarder my domain registrar provides me for my DNS contacts is suspicious:

Hi Ross,

We recently contacted you regarding advertising for one of our clients.

We pay an annual fee to you as soon as the advert is live. It is a straightforward process and we work with you to make sure we fit naturally with your site. Please let me know if you are interested and I’ll send you more details.

Would you be interested in selling us a simple text based advertisement on your website

Best regards,
xxxxxx xxxxx

This e-mail message is strictly confidential. It is intended solely for the person or organisation to whom it is addressed and contains confidential or privileged information. If you have received it in error, please notify immediately and destroy this e-mail and any attachments. You must not disclose, copy, distribute or take any action in reliance on this e-mail or any attachments. Views or opinions presented in this e-mail are solely those of the author and do not necessarily represent those of More Digital.

More Digital does not accept liability for any data corruption, interception, unauthorised amendment, viruses and delays or the consequences thereof relating to this or any other email. Any e-mail or attachment is opened at your own risk.

To help protect you, this email (ID-##########) was scanned for viruses by Norton AntiVirus.

Weird. Do a google search, it’s not a great reputation. Do they really get anyone to bite on these things?


KBC Poker keyboard

2012-06-18 , , ,

I bought an open box, all but unused KBC Poker keyboard with Cherry Blue MX keys as my “travel” keyboard back in September 2011. It’s the size of a standard keyboard with the number pad, function keys, and arrows lopped off. It has clicky, full-travel keys with a normal pitch. Great for fixed mobile typing.

The problem with this little keyboard is the <ESC> key. There isn’t one, or more precisely, there is but it’s accessed by holding down a function-key to the right of the spacebar and hitting the tilde at the top left corner of the keyboard. I’m an Emacs user. The time at work I don’t spend in meetings is spent in Emacs. I have years of configuration and muscle memory invested in using it. You might be asking yourself by now, “What does he think is wrong with the Apple keyboard?” Nothing really, but I strongly prefer the feel of a mechanical key switch. If you spend eight to ten hours a day typing, preferences matter.

The solution is KeyRemap4MacBook, a free System Preferences extension that lets you remap your keyboard and change key behavior. It can do all kinds of things with pointers and key mappings (most of which I’ve never explored) and found the following settings work just fine with the KBC Poker:

  Don't remap an internal keyboard
  Don't remap any pointing devices
  Don't remap Apple's keyboards
  Don't remap Apple's pointing devices
Change Backquote(`) to Escape if no modifiers pressed

After seven months of use a couple of days each week, I’m fairly satisfied with the keyboard and the work-around (certainly for the price). I like the mapping of the Mac volume keys and the function keys but prefer not to have to switch key layouts when I’m at my main desk and I find distracting the small amount of flex in the plastic case and key mounting. I’ll continue saving up for a Happy Hacking 2 Pro keyboard (and probably will be saving for quite a long time).


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