Perhaps the biggest limitation of VoIP phone systems has been what we used to call Cordless.
Cordless, wireless, mobility – whatever- The promise of a cord-free phone extension.
VoIP offered the user so many new capabilities and benefits – the big ones, teleworking, unified communications, and the elusive free long distance. The reality is/was that VoIP wasn’t really needed for any of these. Case in point – after Mitel launched all of these on their IP product lines – they reintroduced them on their TDM products.
However, VoIP did make one promise that absolutely required IP technology – wifi phones. This wasn’t such a good promise. The idea was simple enough. The promise of VoIP and wifi was a “cordless” phone that could travel the entire organization instead of being tied to a 30′ radius leash like the analog variants. In fact, to be clear we were not talking about those legacy Radio Shack type analog cordless phones (typically using spread spectrum) we renamed the technology from cordless to wireless.
The idea was great. Cordless phones were not only limited in their range, they typically were limited or deprived of full PBX features. Some phone system vendors like Toshiba offered cordless digital extensions, but most vendors had nothing better to offer than a Radio Shack analog/cordless phone. So the new wireless phones would address function and distance. They should have been an overnight success.
Problem was VoIP wireless phones were harder than we thought. The popular wireless standard was 801.11b which at 11 Mbps was sufficient, but the Access Points (APs) were hubs not switches. This meant that only one device can talk at a time. VoIP requires switches. One simple solution was voice APs and data APs – with the voice APs limited to 1 or 2 phones. Another solution was to introduce voice prioritization techniques – but since 802.11b didn’t address voice prioritization, it would mean proprietary solutions.
The first major vendor with a reasonable solution here was Symbol – proprietary Symbol Access Points that supported 802.11b and proprietary Symbol wireless phones. Another thing the Symbol phones did was address the AP to AP hand-off for the mobile user. The hand off between APs was something else the 802.11 standard didn’t get around to. So typically the only way to do hand-off for mobile users was to use like branded APs. We implemented the Mitel version in 2002 that ran the Mitel proprietary VoIP protocols and it worked pretty well. We almost had a solution, but these APs were expensive. They were as high as $1k, competing against Best Buy APs for $49. The next problem was Symbol discontinued the phones. Oh well.
A few wifi phones started appearing in the Asterisk/SIP circles. But early SIP was a nightmare in terms of interoperability – and then another limitation still had yet to be solved – battery life. Wifi phones consume a lot of power. These wireless phones were spending a lot more time in their charging cradle than anyone expected.
So for the past several years, we have been telling the mobile hearted to head to Radio Shack for their cord-free solutions (AKA cordless). The serious customer did have one other option – the solution from Spectralink needs to be mentioned. Spectralink – acquired by Polycom last year – has always understood cordless/wireless or cord-free. Mitel replaced Symbol with Spectralink not long after Symbol killed their phone. Spectralink offers both wifi and digital solutions. They work well. I think I prefer their digital solution (emulates digital phones) as it was more mature. You can find these at most Barnes and Nobel’s (on Toshiba systems) as an example. The wifi variant also works well, but requires very high-end APs and a proprietary Spectralink Server for voice prioritization. Their phones are also pretty expensive, so all in all this was not a solution for the general population.
But in the past several months, we have seen evidence that cordfree solutions for VoIP are coming. It is back to the SIP world – Polycom released their first DECT solution. This was a result from their acquisition of Kirk Telecom (UK). DECT technology – very popular in Europe for cordless phones – was heading to the US. Prior to the 5020, there were a handful of DECT phones available – but not IP – just for high end POTS users.
With the Polycom/Kirk 5020 – you could have a SIP base for the DECT solution. The SIP/IP went to the base and the base to the phone connection utilized DECT. The benefit was a mature radio technology – low battery consumption, crystal clear voice quality, low chance of interference, and the ability to hand off between base units – the original promise. So what if the IP part was only to the base unit.
We implemented our first 5020s a few months ago. They work well – exactly as promised. Their major limitation is they are only single line phones.
Snom recently released the M3. I haven’t seen one yet, but they appear to be a logical next step. They support 3 lines per phone and they have an option of a shared directory/phone book. The Snom M3 has a similar architecture to the Polycom/Kirk phones- SIP base/Dect phones. They have a limitation of only 3 active calls per base and I have heard they did not address AP to AP hand off (both presumably to be fixed in later software versions).
Both the Snom and the Polycom/Kirk phones are fairly new to the scene. Most of the proprietary VoIP players are slowly embracing SIP. I would say the wifi promise is dead, but IP mobility is finally coming.
There is one exception though where wifi phones still have a chance. Many of the new cell phones that support wifi (Blackberry, MS Mobile, even possibly the iphone) have the ability to load a SIP based soft phone. I have seen this demonstration where the LAN/wifi cell phone actively takes calls off the PBX via wifi/SIP. It is really pretty simple from a demo perspective, but from a practicality perspective it is pretty limited (highly limited soft phones and extremely limited batteries). Not sure this will make it out of the lab, but it is slick.
the VoIP wifi future may come via 802.11N, better batteries, and better cell softphones – this solution still has potential, But for now, I am banking on the DECT variants.