Battery Life and Range
One of the most common failings of Wi-Fi SIP phones is poor battery life. This is not entirely the fault of the phones. The radios used in Wi-Fi are designed for optimum network performance and reliability, not conservation of power. In contrast, the DECT standard provides for close management of power consumption.
The m3 includes a Lithium-Ion battery to further maximize battery life. snom claims eight hours of talk time and 100 hours of standby time. My experience has been that I can leave an m3 off its charging stand and use it heavily for two days, and still have 25% of battery power remaining. This is much better than my last Wi-Fi SIP phone, which could barely manage two hours of talk time on its NiMH battery.
The m3 specifications claim a useful outdoor range of 100m (300 feet), or 50m (150 feet) indoors. In a simple test walking around outside, I was able to go 90 feet away from the base station before call quality started to degrade. This is more than adequate for my purposes, as it covered my entire property. To get the claimed 300-foot range, I think you’d need an unobstructed line-of-sight to the base.
One aspect of the DECT standard is that it provides for seamless handoff of ongoing calls as a handset moves between coverage areas provided by multiple base stations. Given the range that I’m seeing with one base station, I can’t justify the cost of the second base, but it’s easy to see how this could be used to create uniform coverage over a very large area.
A built-in intercom function allows for calls between handsets without passing the call through an outside SIP server. The intercom function also supports calling all handsets at once (Figure 7). This could be handy if you’re trying to reach someone in a large house or office and you don’t know where he or she might be at the moment.
Figure 7: The intercom function supports calling one or all handsets
At the very cutting edge of VoIP is a group of people who exchange contact details in the form of SIP URIs. As opposed to the 10 digit numbers common on traditional PSTN lines, SIP URIs use a format similar to an email address. For example, firstname.lastname@example.org is an actual SIP URI that points to my personal line via Junction Networks OnSip hosted PBX.
I was a little disappointed to find that the m3 doesn’t handle SIP URIs, either for dialing or in the contact list. It seems to be just a matter of not having access to alpha characters in the entry screens used for dialing or contact details. I would hope that this would also be addressed in future firmware, although I accept that it’s not a problem for the vast majority of users.
snom has long been a leader in SIP compliance testing with their line of desk phones. Adherence to the SIP standard ensures seamless device interoperability. The m3 has proven itself to be very reliable in this regard. On my office network, it was used with several Aastra and Polycom phones. It never dropped a call when used with a hosted IP-PBX, nor when used with my local Asterisk server.
The basic snom m3 kit with one base and one handset retails for $245, with extra handsets going for another $150 each. It’s priced beyond the range of the common household application, but is more than competitive with other business-class solutions, such as the Aastra 480i CT. It’s also considerably less expensive than the enterprise-class SIP/DECT systems from both Polycom and Aastra.
snom’s m3 is a very capable business-class cordless IP phone system. snom has positioned the phone to appeal to savvy SOHO and small business users. When combined with a hosted IP-PBX, it can provide a complete and compelling solution for non-technical users. For those with greater needs, it’s equally functional as part of an Asterisk installation. The m3 is without question the best cordless IP phone system I’ve tried to date—perhaps good enough to keep me from looking further.