Beware ZDNET on VOIP

A couple of weeks ago someone posted a link to a some ZDNET VOIP resources to a mailing list that I read. The link (here) brings up a page called ZDNET News At The Whiteboard where there are posted some short videos explaining various topics.

The first video in the series is “The future of VoIP: CoIP” where COIP is their term for “communications over IP.” The speaker, someone from Yahoo, goes on to explain how text (meaning IM), voice and video are converging. More specifically he says that all of this is centered around the instant messaging client. Watch the clip, it’s not that long.

It’s also not that insightful. I mean, really, what is their point? How is this news? To put it into mathematical terms easily displayed on their whiteboard:

IM + Voice + Video > Voice….which is true.


Voice > IM


Voice > Video

I find it interesting that companies in the IM space presume that communications will naturally cluster around the IM client. This is not necessarily true. An IM client is not necessarily a productive or sensible approach. Consider people not at a PC. Consider even smart phones, like my Blackberry Pearl. I have a couple of IM capable clients loaded but I rarely use them. It’s just not convenient. Making a call is just more effective. IM is better than a long email thread back and forth on a topic, but even then email provides more permanent history.

I think that they also overvalue video as a component of the solution. People just don’t think that it’s worth the trouble. Skype has offered video for a long time. Many people I know, myself included, bought the hardware and tried it out…then just don’t bother most of the time. The Video Phone was introduced in the 1960s and has never really caught on in a big way.

Ultimately these people are underestimating the value of the voice portion of their solution. I would argue that phone calls are essentially universal…everybody makes them. IM and Video chat see dramatically less uptake amongst real users. Not that there aren’t numbers there, but in that little mix of channels voice is still the king by a wide margin.

Furthermore, Jeff Pulver has been talking about “IP Communications” for a long, long time. COIP seems just to be some marketing pitch for their IM-centric view of the world.

It also bears mentioning that all this convergence is happening in the realm of IP. But then, the whole world is migrating to IP networking so that’s not exactly news either.

I’m left asking what was their point? I don’t get it? Why all the excitement? Or better yet, who needs this explanation?

I expected better from ZDNET. Their IP Telephony blog by Russell Shaw is usually excellent.

VOIP Uptake By Trixbox Users Rising

Kerry Garrison of Fonality appeared on The Voip Users Conference Friday December 21 to address the recent fervor over the matter of Trixbox implementing a script to automatically send system details back to Fonality. Kerry did a good job in front of a tough crowd. As a company they have admitted their error and appear to be redirecting themselves to a more appropriate approach. “Mea culpa’s” are hard, but they appear to be doing the right thing in this case. You can listen to the MP3 recording of the call to get the details.

Presuming that the opt-in version of the program is launched there is no doubt that the information that they could gather from their user base could be very interesting. They will be able to tell what sort of phones are being deployed, what version of each app is being used, what sort of connectivity is deployed, etc. Very interesting stuff.

In particular Kerry was able to say that in 2007 around 40% of their users are leveraging VOIP providers for core services. And further, this is double the uptake from the previous year. That is, people are using IP-based DIDs and termination services instead of, or addition to, traditional TDM (T-1, E-1) or analog lines (FXOs.) So it appears that confidence in VOIP service providers is increasing.

This certainly echos my own experience. I have not had a traditional land line in over two years. I’ve used a number of ITSPs, some good and some not-so-good. But I also find that they are steadily improving. To a degree this flies in the face of the spectacular and much publicized collapse of Sun Rocket earlier this year, as well as a number of others.

The past few months there’s been an increasing amount of FUD circulating about VOIP service providers. Vonage, Sun Rocket et al have impacted public perception of the space. This information reveals that there is good news as well, it’s just not as well known.

H-P T5700: A Few Words in Praise of Something Small

One of my major mania’s is catching on. Josh Richards just blogged about trying Askozia on an H-P T5700 thin client. These are great little devices. I was so lucky to stumble into a source about 18 months ago. A major corporate concern was about to pay to have a few boxes of these little wonders “recycled” by Dell. A friend and I intervened and relieved them of that necessity.

At present I have three of these running in my home office.

  1. Astlinux 0.48 in production
  2. An Askozia testbed
  3. FreeNAS with SlimNAS

With a 1 GHz CPU and 256 MB RAM (more if you upgrade the one SODIMM ) they are reasonably powerful, certainly enough for a small Astlinux or Askozia installation.

HP T5700 Rear Panel
HP T5700 Rear Panel

The third unit is perhaps most interesting. FreeNAS is a NAS software based upon FreeBSD and the m0n0wall framework. Like m0n0wall it’s simple, just enough to do what you need and not a lot more. It runs great on the T5700. However, a NAS needs storage, a lot of storage.

T5700 Internals
T5700 Internals

The T5700 has an internal IDE connector that’s fitted with a 256 MB flash disk-on-module (DOM). You could swap that our for a 2.5″ HD with the right sort of adapter, but laptop hard drives have high $/GB and less than ideal MTBF.

The T5700 also has a number USB ports but these are USB 1.1…less than ideal for interface to portable hard drives. I was able to find the optional expansion chasis on Ebay for $20 each. This lets them take one standard PCI card, in my case a 4 port USB 2.0 card. Then I could connect a couple of external hard drives and…voila…cheap, silent, spacious NAS…with software RAID if you like.

One of the major uses for NAS around my home is music. I have a couple of Slim Devices Squeezeboxes as music playback for the home and office. These are outstanding devices! Truly change-your-life gadgets. They connect to your stereo and stream music off a PC server running a Perl based server software. It just so happens that Michael Herger has created a package called SlimNAS that installs the Slim Server software into FreeNAS. So this little box not only stores the music, it serves it up as well. All in <10 watts.

There in one little gotcha. You can set the BIOS to boot from a USB port, but it will only boot to the devices on-board ports. It won’t boot to a USB 2.0 port on a PCI card. This is minor. I built a 1 GB thumb drive with FreeNAS and SlimNAS, then added a pair of 250 GB HD in USB portable enclosures that I had sitting around. That’s 500 GB of RAID 0 or 250 GB of RAID 1 storage. Total power consumption < 25 watts. Ambient noise contribution to the room…none.

These are great little boxes!

CPU Requirements For Transcoding To/From G.729a

During the VOIP Users Conference call on December 14th someone made some claims about the ability to handle G.729a encoded calls on various platforms. The comments revolved around the significance of cpu cache when dealing with the G.729a codec. Also some claims of the ability to deal with very high numbers of calls. The claim about the numbers of simultaneous transcodes possible were troubling to me.

G.729a is one of the more complex codecs in the VOIP universe. It puts considerable load on the CPU of the system that must for whatever reason transcode the call. In particular it’s FPU intensive. While CPU architectures are deeply interesting to me, suffice it to say that on some hardware platforms floating point operations are amongst the slowest operations that a CPU may perform.

Of course transcoding is not always necessary. A call may be placed from a phone that is itself G.729a capable, through the local Asterisk instance to an ITSP and on to the recipient…all of which are also G.729a capable. The call can thus be made without any transcoding at all. However, at any point along the path the a stage may not accept G.729a stream and so the call gets transcoded into something more acceptable, perhaps G.711 or GSM. Most typically calls that get routed to voicemail are transcoded to G.711 for the VM subsystem, although not always. Asterisk always transcodes into G.711 for MeetMe conferences.

I know for a fact that the Soekris Net4801 embedded platform can handle two G.729a transcodes when suitable licenses are installed. I used this very arrangement for over a year, and even wrote an article about it here.

Soekris Net4801 with the cover removed
Soekris Net4801 with the cover removed

The Net4801 features a National Semiconductor Geode SC1100 CPU running at 266 MHz with an unspecified amount of cache. When I first started using G.729a on the Net4801 I inquired with Kristian Keilhofner, the lead author of Astlinux, about his experience with the board. Kristian told me that 2-3 simultaneous transcoded calls was the most I could expect due to CPU limitations. My own experience supports his assertion.

T5700 Internals
T5700 Internals

More recently I’m using a HP T5700 thin client which features a Transmeta Crusoe CPU running at 1 GHz and with 512 kb of L2 cache. Under test conditions I’ve had four G.729a transcodes ongoing on this platform, but my test was limited to having only four licenses installed. I suspect that it could handle a few more channels, but the CPU use with even four concurrent channels points to a hard limit perhaps around 10 channels. I may well test this myself some day soon should the need arise.

Finally, Digium’s TC400b PCI card is specifically built to accelerate transcoding and offload that task from the host CPU. According to Digium, “The TC400B is rated to handle up to 96 bi-directional G.729a transformations or 92 bi-directional G.723.1 transformations.” If this is the stated capability of their accelerator then it seems unreasonable to expect similar or greater performance from a small format embedded platform, whatever the CPU cache might be.

The statements mentioned previously indicated the potential for a dramatically larger number of transcoded calls than would seem to be possible on the given platform. I find this unlikely on the basis of personal experience, the opinion of others whom I respect and Digium’s own statements about their transcoding hardware.

If you need transcoding capability on a low cost embedded platform it can’t hurt to consult with sources you trust. Ultimately you should conduct your own testing to be certain that the hardware supports your requirements reliably under real-world circumstances.

A Gift Idea for the VOIP User

When it comes to holiday gift giving my wife has to ask me for a list. Otherwise she knows that she has no hope of getting me anything techy that I’ll actually appreciate. In some ways, for those of us steeped in technology, buying a gadget is a deeply personal thing.

I’m an unabashed VOIP fan. Add to the mix the fact that I travel quite frequently. The conjunction of these two facts brings to light one of the best purchases I’ve made in the last couple of years; the Polycom C100 Communicator. A great holiday gift idea.

This little USB speakerphone device is really very good. I’ve tried several and it’s by far the best of the bunch. At around $120 USD it’s not the cheapest, but it’s not the most expensive either.

I tend to use it with X-Lite, Gizmo and (gasp!) Skype. It’s really just a USB audio device so it should work happily with all soft phone clients, even TringMe and the like.

The USB cord is attached, which is a bit of a drag, but it winds into a storage area located under the device when the pop-out stand is opened. The design is very nice. The device is physically robust and should suffer many accidental indignities without breaking.

The audio quality is excellent, just as you would expect from Polycom. Supporting their HD Voice technology this is about the cheapest way to try the new G.722 codec for wideband audio with 22 kHz sampling.

For the person giving the gift it’s merits are many. It only comes in one size, although several colors. It’s small enough to be inexpensive to ship (or fit in a computer bag) and of course, being from Polycom, it’s an indication of your good sense of taste, and concern for quality.

I’d post a link to an online e-tailer, but these are generally available and I don’t feel the need to drive traffic to any one particular source. I bought mine at a brick and mortar retailer, The Micro Centre, simply because it was on the shelf and I was standing right there. Just Google it.

Of course, you can always add it to your own list. You can’t go wrong with this device.

A Tale Of Woe….And Cordless Phones: Part 1

I was trying to not write this, but week upon week the trouble persists, and my search for a cordless phone continues ad nausea. This entire story I’ve now told to several people who hazarded to ask, “what’s wrong?” So now I write just to stop my hands from shaking, that I may eventually rest.

I need a cordless phone. Full stop, let’s consider that fact for a moment. Working in my home office, when home at all, I frequently attend long conference calls, or provide deep tech support and diagnostics via phone. I can spend a lot of my day on the phone. This is part of what drives my earlier assertion that “Life’s too short to use a cheap phone.” Call me a phone snob if you must. I don’t care.

Here’s the next fact of the case. I’m an early adopter. I buy stuff early in it’s life cycle just because it looks like it might be cool. Sometimes it is cool. Sometimes it isn’t, but with guidance it gets there. Other times it just doesn’t live up to its promise, and we move one having learned some lessons. Early adopters spend more than most to be early in the game…those of you in manufacturing take note.

Returning to my original statement. I need a cordless phone. Cross that fact with the fact that I have Asterisk in-house, as well as hosted PBX via my employer. So I can be more precise….I need a SIP cordless phone.

A Collection Of Wifi SIP Phones
A Collection Of Wifi SIP Phones

VOIP Supply lists no fewer than 12 SIP WIFI phones. You’d think that one would meet my needs. And you’d be wrong. Further, I’m betting if they don’t work for me they won’t satisfy the bulk of you either. So why are so many manufacturers bothering with Wifi SIP offerings? And where are they going wrong?

Hitachi Cable WIP-5000
Hitachi Cable WIP-5000

Let me say that I’ve definitely put my money into this quest. I bought a Hitachi Cable WIP-5000 directly from the importer when they were just being rolled out in the US. I paid over $350 for that device, more than any other phone I’d ever bought at the time. Even more than any cell phone I’d owned. It looked promising so I made the investment in both cash and time.

After four months using the WIP-5000 I put it back in the box and used the magic of E-bay to deliver it to a new home. Why? There are a lotta reasons;

1. Volume too low

Both in the handset and when using an earpiece. And I work in a relatively quiet home office. How anyone could use that phone in a busy office I’ll never know.

2. Battery life too short

A simple problem. I got about 2-3 hours talk time or 36 hours standby time.

3. Coverage too unreliable

Using common wifi APs, that is the <$100 devices as opposed to Cisco AiroNet, wifi coverage was not consistent enough to sustain a call more than about 10 yards away from the AP. I use two APs to provide coverage across our property. The WIP-5000 could not hand off from one to the other while sustaining a call.

These are the technical reasons why the WIP-5000 didn’t meet my requirements, but there are underlying design considerations that go unspoken as other manufacturers have rolled out more and more wifi handsets.

Now Hear This!

A cell phone is not the ideal form factor for a cordless phone!

Wireless <> Cordless!

If you look at essentially all the wifi sip handsets being offered they all presume that a cell phone is the ideal form factor. Some even go so far as to mimic the clamshell designs. For dedicated wifi sip handsets this is simply wrong. Wrong in so many ways.

* Buttons too small
* LCDs too small
* Limited access to PBX features/functions
* strange power connectors
* No integration with contact lists from server
* No belt clip
* etc, etc.

To illustrate my point lets consider one of the most successful companies in the corldess phone space, and a product that I once used (and loved)…Panasonic’s KXTG-4000 KSU system.

Panasonic KX-TG4000B KSU with built-in battery backup

This was a great system for SOHO users. It had 4 FXOs, supported 8 cordless handsets, which were available both in handset and deskset form factors. So smart! Why did I love thee so?

* The handsets are large-ish, with buttons big enough to find while fumbling one-handed.
* Common pbx functions like hold transfer & redial each have dedicated buttons.
* Long range, as much as 100 yards
* Battery life is long, and the battery is end-user replaceable.
* There’s a belt clip, big enough not to let go if I bend over
* Durable, handles being dropped fairly well
* A standard wired headset jack
* Caller log & stored number directory are easy to use with a minimum of button presses
* Stored number directory can be sync’d from the base to the handset and vice versa

Now it wasn’t perfect. As a 2.4 GHz device it didn’t interact well with wifi networks. This model was replaced with a 5.8 GHz model that was a better fit into wifi enabled facilities.

Has anyone even noticed that Panasonic has a long and successful history in the cordless phone business? Does anyone even acknowledge that as a business, one that’s very different from the cell phone business?

Aastra 480i CT With Cordless Handset
Aastra 480i CT With Cordless Handset

The nearest thing to this in a SIP phone is the Aastra 480i CT, or the newer 57i CT. I bought a 480i CT which I really do like a lot, but its portable handsets are very small, with no dedicated keys at all. It’s a great SIP phone, but the cordless units are much less than ideal.

It’s worth noting that the Aastra phones are not wifi devices, they’re DECT based. DECT is a European standard in the 1.9 GHz band that was only recently adopted in the US. As such, these devices are wifi friendly. They also have reasonable range, easily comparable to my old Panasonic KSU.

Engenius 900 MHz Cordless Phone
Engenius 900 MHz Cordless Phone

I’m almost embarrassed to admit that I once purchased an Engenius long range cordless phone. At the time these were the very best option for commercial installation. Notice how the handset looks like a mid-1990s vintage Nokia cell phone? As far as I can tell this was when the cordless phone world turned the corner, in the wrong direction, and started trying to mimic cell phones.

This device worked as promised. And when used with an ATA it handled basic calling adequately. However, an ATA and a traditional cordless cordless phone puts the burden of accessing pbx features into the dialplan. You have to code all the different functions that would be natively appearing on a genuine SIP device. So that’s a double whammy, no dedicated button, and non-standard dialing to access PBX functions. Deduct several million points for usability.

In the end I stopped using this device because of short battery life and poor audio quality. It had a NiMH battery that suffered memory effect, and no upgrade path to a Lithium Ion power source.

This product is now defunct, but their current offering is a SIP wifi handset…with tiny little buttons and little or no access to pbx functions.

Sadly, this new device is essentially the same as the handset being offered by 3 Network in the UK, and known as the “Skype Phone.” It seems that there are only a few designs floating around Asia being branded by various companies in The West.

In part 2: Surveying the DECT SIP landscape, Polycom/SpectraLink, Aastra SIP-DECT & the new SNOM M3