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Posts from — April 2014

A Behemoth Book To Reivew

PLC Book

I just received my copy of Programmable Logic Controllers: An Emphasis On Design And Application.  When I saw a used First Edition on Amazon for $50, I snapped it up.  (I looked at the differences between the First and Second Editions, and decided that the Second Edition didn’t add anything I needed).

I am planning on writing a review, but it’ll be a while since the book has 1461 pages — but that means on a per page basis, it’s much cheaper than Cascading Logic!  (And, yes, I still do recommend Cascading Logic, but it is overpriced.)

Two PLC Books

Two PLC Books

PLCs: An Emphasis… Cascading Logic
List Price $85.00 $89.00
Type Hardcover Softcover
Pages 1504 206
Weight (oz) 80 14.5
Price Per Page $0.056 $0.432
Price Per Oz $1.06 $6.14

April 29, 2014   2 Comments

Obi, Codecs,WiMax, and the End of GV XMPP

It’s time for an Obi update.  As I’ve mentioned before, I really like my Obi 202; it’s a nice combination of reasonable simplicity and flexibility.  However, Google is dropping the XMPP interface to Google Voice on May 15, and Obihai isn’t going to try any work arounds, so I’ve had to re-configure my system.

What I’ve ended up with is this:

  • Currently keeping the Anveo DID (incoming phone number) which I’ve had for several years.
  • I’ve added Vestalink as my main service (incoming and outgoing).
  • I’ve also added Localphone, currently on a 800 minute/month subscription for outgoing ($1.60) and DID for incoming ($0.99/month; I’ll probably drop the DID).
  • Both Vestalink and Localphone are set up spoof our Google Voice number for outgoing calls.
  • I’ve set Google Voice to forward to Vestalink for incoming GV calls.

It’s working pretty well, especially by the most important standard: my wife hasn’t been complaining.

Consider I was paying >$20/month for basic metered local telephone service, I’m not worried about saving every penny.  I like having some redundancy, so if say Vestalink is having trouble, we can always use Localphone.

I did not use any install wizards; I prefer to enter the information in by hand, so I can tweak it if necessary, move things around, etc.

Codecs and Wireless

The only big tweak I’ve done is with codecs: I’ve setup both Vestalink and Anveo to only use the G.729 codec (GV and Anveo only support G.711).  The G.711 codec might have slightly better quality than G.729 (according to one study I found, 4.3 vs 4.0) on a fast wired connection, but it doesn’t recover well from lost packets, jitter, etc.

So I’ve been happier running VoIP on FreedomPop WiMax after I’ve switched off the direct Google Voice connection to my new G.729-based services.  I give the credit to the Obi forums; I’ve learned a lot from them recently.

I will also be experimenting with Android SIP clients.  In the past, my experience wasn’t too great, but I think using G.729 might help.  Vestalink provides their own client (a customized version of Cloud Softfone), and allows two simultaneous calls (so if I’m talking on Android, my wife will still be able to call at home).  For Localphone, I am evaluating CSipSimple and Zoiper.  I’m not planning on using SIP for incoming; SIP apps appear to significantly decrease battery life.


Vestalink has had its issues such as a few outages and issues with delays with calls forwarded from Google Voice, so YMMV (your mileage may vary), but I’ve been satisfied.

So far Google Voice forwarding to Vestalink has been great, with almost instant or very short delays.  Voice quality has been fine (considering I’m on WiMax).  It’s easy to set my outgoing Caller-ID.  I like the incoming CNAM (name lookup).  Vestalink does have a 30 day trial period.


So far Localphone has been working fine, too.  I’ve tried some Google Voice to Localphone DID forwarding, and it’s been fine, even though the packets supposedly have to go Europe and back.

Other Options

I chose based on my priorities and current usage.  There are a number of other options worth considering, especially if you have different needs, including:

  • The Obi plans.  Current choices include three plans from Anveo and two plans from PhonePower.
    • The Anveo plans have fairly limited outgoing minutes.
    • You have to sign in to see the details.
    • These plans are setup over the internet, so it’s almost as easy to use as Ooma (but still more flexible).
    • I thought about the PhonePower plans, but passed  because I want to be able to tweak settings, including my Caller-ID spoofing (PhonePower doesn’t allow easy spoofing changes).
  • A free Callcentric DID for incoming + Localphone or CircleNet for outgoing.  Note: if provide a US or Canadian address, Callcentric charges $1.50/month for E911.  Localphone is typically about $0.005/minute, with US packages of 800 min/month for $1.60, and 5000 for $5.00.  CircleNet says most calls are under $0.005/minute.
  • Future-9, although you have to check the Obi forums or DSL Reports forums if you are interested in their interesting $5/month plan.
  • Callcentric.
  • Skype via a bridge.  I had thought about this, but decided it was too much hassle.
  • I’m sure there are others; I highly recommend participating in the appropriate Obi forum; for North America, it’s here — I have learned so much from there.

Additional Notes (Added Later)

  • Google Voice is currently still working with Obi ATAs, but there is no guarantee how long this will last.  I think it’s better to switch now; I have no regrets paying a bit and getting more (such as a better CODEC for my internet connection and  incoming caller name lookup).
  • With all services, results may vary.  For example, I’ve seen reports that LocalPhone has problems calling some Verizon land line numbers.

Even More Notes (October 2014)

  • After Obi changed the authentication method for Google Voice, it’s now officially supported again.  However, that could change yet again….from what I’ve heard, Google really was planning on shutting down XMPP, but changed their mind.
  • So if you want to save maximum money, Google Voice is probably the way to go.  However, you can get many extra features (such as Caller ID lookup (CNAM), E911, and such) with a SIP provider.  I’ve found I really like having CNAM.

Dec 2014 Notes

  • Looks like Future 9 is out of business.  Vestalink is still in business, and I hope they can find a sustainable business because VL has worked well for me.
  • My Anveo DID seems to be having substantial lag reporting the Caller ID number.  I’d also like CNAM on that number, so I’m considering porting it to another carrier when my pre-paid account gets down to $1 or so (possibly CircleNet.  Yes, they’re another small provider, but I think their business model is sustainable).
  • Newer Obi’s can also use  service; it’s likely older Obi’s (like mine) will get it eventually.  I’ve played around with it a bit on my phone (since I’ve had GrooveIP for a long time), and so far it’s been a bit flaky (won’t authenticate over my LTE MiFi, but will over WiMAX).  Opinions on the Obi forums are mixed.

April 27, 2014   1 Comment

Notes from the EE Live! 2014 Exhibition

In early April I managed to sneak off work for a day and wander down to the San Jose Convention Center for the EE Live! 2014 Exhibition (formerly known as the Embedded Systems Conference).  The ESC has had its ups and downs, going from the San Jose Convention Center (which I like a lot) to the Moscone in SF (bigger, but not better), back to the SJCC, and next year, down to the Santa Clara Convention Center (which is a pretty nice setup, but not the location for major shows).

I skipped ESC last year, so I was surprised how much the show has shrunk.  On the plus side, there was a lot of exhibition floor training sessions, and all the ones I saw were well attended.  In fact, NXP skipped the product booth and only did training.  Since I do enjoy harassing talking to sales dudes and want to encourage companies to come back, I spent most of my time at the vendor booths.  Here are my show notes, which reflect my interests (which tend towards industrial applications, MCUs, and DSPs):

  • I was surprised at the size of the x86/x64 contingent: Intel, AMD, and a trio of motherboard manufacturers (Asrock, Supermicro, and MSI).  There were also several flash vendors.
    • I have to put in a plug for ASRock, because my desktop PC has an ASRock motherboard, and when it had a minor problem (PS/2 ports quit working), ASRock’s service was quite good.  However, the industrial division is separate (and much smaller), selling compact industrial motherboards direct or through distributors such as Logic Supply.
  • TI had a pretty big booth, showing off their more embedded-oriented lines (no C6x DSPs or analog), including the BeagleBone and the various LaunchPads.
    • TI’s EE Live! 2014 videos are available on Youtube.
    • TI still did their tool swap, so I traded an old Philips 8051 CAN dev kit for a shiny new Tiva Connected LaunchPad, which I have since donated to an eLua volunteer.  TI said the Connected LaunchPad was very popular.
    • I had fun discussing industrial safety (standards, light curtains, safety PLCs, and such) with the Hercules guys – and verified that the RM48 Hercules MCUs do indeed support double precision floating point.
    • It’s always fun to see motors run, and TI was demonstrating their InstaSPIN techology with a conveyor.  I had fun complaining about too many serial encoder protocols (Biss, EnDAT. SSI, Panasonic, Tamagawa, etc).
  • Microchip had a pretty big booth, with a wide array of products.  The new PIC32MZs are pretty impressive, but what I wanted to see was their metal-over-cap button technology.  Microchip has been improving it; this year they showed off metal dome capacitive buttons (my favorite, since they had good tactile feedback) and backlit buttons.
    • Microchip App Note AN1626 [PDF] has lots of interesting information on how to design and backlight metal over cap buttons.
    • The backlit buttons were a demo of Demmel’s metalLight technology.
    • The tactile buttons were a demo of grafos steel’s Click-Inox technology.




  • ST ran a lot of in-booth seminars;  I listened to the mbed presentation for a while (and now want to learn more).  I didn’t spend much time looking at their products since I’m pretty familiar with them.
    • ST was giving out STM32F401 Nucleo boards if you were lucky enough to get a goody bag (I managed to snag the second-to-last bag).  This Nucleo includes the sweet STM32F401 MCU, Arduino headers, and mbed compatibility (SDK (Software Development Kit) and HDK (Hardware Development Kit)).
  • Atmel didn’t have a booth: instead they had their roadshow trailer.  The coolest demo was a 3D printer, powered by Atmel of course.
  • NI had a booth showing off LabView and their hardware, including a motion-and-vision demo featuring Kollmorgen drives and motors.  I spent most of my time there discussing industrial applications with a guy from Xilinx who is interested in industrial applications (such as real time Ethernet) for FPGAs.
  • I took a class from Rhode & Schwarz on oscilloscopes basics, and received a free Digital Stimulus Board for my time.  My big take-away from the class: short, good grounds are critical (long, looping ground wires can be great antennas).  Their oscilloscopes are impressive and fun to play with, but quite a bit more advanced than I need.
  • I stopped by Pico Technology briefly to see what was new.  Pico makes what are probably the highest end USB oscilloscopes.  Some of the newest models support USB 3.0.  Another series has variable resolution (you can trade slower speeds for increased resolution).  Most of them are fairly large.  I asked about USB latency; the salesman said they used some tricks, but noted that they perform a lot of processing in the scope using a FPGA, so the USB connection isn’t as critical.
  • Vision Components was showing off their OEM smart cameras, so I stopped by as always to see what was new.
  • I stopped by Acces I/O and chatted about industrial Ethernet protocols and data acquisition.  Their USB-DA12-8A is one of the more affordable options if you need a precisely timed DAC output.  And they might have some good stuff coming in the Ethernet DAQ arena.
  • I talked briefly with Sealevel Systems; they make a variety of industrial grade computers, serial interfaces, digital I/O, and analog I/O.
  • Trinamic was showing off their stepper and DC motor drive chips, boards, and enclosed drives.  Although they’re not the best fit for my current requirements, they’re worth checking out, and have some low cost models (especially for the chips and boards).  Some models support CANOpen or EtherCAT.
  • Silvertel was showing off a variety of PoE modules, with prototypes up to 200W.  They claim their module pricing is cost-competitive with rolling your own up to medium volumes (say 1000’s or 10,000’s per year).

April 23, 2014   No Comments