snom, a Germany-based company, may not be the best known player in the
VoIP space, but they produce a family of SIP and H.323 phones as well as SIP
proxy/registrars and SIP media servers that can compete feature-for-feature
against any of the ï¿½big boys.ï¿½ When you then factor price into the equation,
snom is often a much less expensive solution. The snom 100 and 200 phones
are Linux-based, compatible with H.323/H.450 or SIP protocol suites and
contain Web browsers as well as SMS functionality. snom utilizes and
supports open source and does not incorporate any special chips or software
in its phones. Thus, snom is not subject to license fees, which add costs
and are dependent on bug fixing by other companies. We checked out both the
snom 200 and the snom 100 and liked what we saw.
It was a strange concept at first, but we fell in love with ability to
actually ï¿½log ontoï¿½ our desktop VoIP phone using a standard browser. The
snom phonesï¿½ integrated HTTP Web server makes configuration and remote
management easy. The companyï¿½s phones also support LDAP and TAPI,
which enables the ability to dial from Microsoft Outlook or look up an
employee in a corporate directory. Other potential applications include
server-based voice recognition, presence, and encryption.
The phones are compatible with VoIP gateways and gatekeepers based on SIP
and H.323/H.450. Features include call list, deny list, call waiting, call
hold, call divert, conference call, transfer, redial, speed dial, SMS
send/receive, echo cancellation, phone book, multiple ring tones, an HTTP
Server, and a graphical display with four soft keys.
The snom 200 features five programmable function keys and two Ethernet
ports. It features a dual line graphic (2x24 character display), six LEDs,
text display and key pad, as well as an AC97-compliant audio subsystem.
Both the 100 and the 200 have a second Ethernet port with VLAN support
enables users to ï¿½daisy chainï¿½ the phone with a PC. Both phone models
feature multiple language support, and very importantly they support power
over Ethernet via the IEEE 802.3af standard.
We tried to get the snom 100 and 200 to work with an old beta version of
Microsoftï¿½s SIP-based RTC Server, but werenï¿½t successful ï¿½ through no fault
of the snom phones. So instead we installed snomï¿½s own SIP server (snom 4S
SIP Proxy/Registrar) and were able to successfully register both the Snom
100 and 200 phones with the SIP server. The 4S SIP Registrar Proxy, is
compatible with SIP phones from snom, Cisco, Pingtel, and Siemens, as well
as being interoperable with Microsoft Messenger (which we successfully
tested). The proxy runs on Windows 2000 and XP, Linux, and Solaris.
In addition, we also installed snomï¿½s 4S SIP Media Server, which enables
media related features such as voicemail, auto attendant, conferencing, and
announcements. (Keep an eye out for a full-fledged review of the snom 4S SIP
Media Server in a future issue.)
Once the phones were registered, we were able to successfully make calls
from one phone to another as well as conference in a third VoIP phone. The
voice quality was excellent with minimal latency. We used Hammerï¿½s Call
Analyzer to determine its VoIP quality and other parameters. First we
measured the MOS score ï¿½ a voice quality measurement that approximates the
ITU-T Mean Opinion Score (MOS) metric by incorporating packet loss, latency,
and jitter. It scored an excellent 4.32 MOS score (0-5 range) as well as
jitter that was 0. In addition it had an R-Factor score of 94 ( 0-100 range,
0-bad, 100-best). The R-Factor score is determined using stream metrics and
the Telchemy algorithm.
We should mention that STUN ï¿½ which is incorporated in all of snomï¿½s SIP
VoIP phones ï¿½ enables you to easily deploy SIP devices over most NAT
routers. snom also supports UPnP, which is another technology for resolving
VoIP across NAT issues.
Fairly unique to the snom VoIP phones is their support for standard PC
headsets since they use the same jacks on the phones as you would see on a
PCï¿½s sound card. We all know that a PC headset is an order of magnitude less
expensive than a phone headset, so this is certainly a cost savings
snom takes user feedback to heart. For instance, they found that too many
users users would move their phones on their desk and the A/C
connector would come loose. They then changed to an RJ-11 connector which
was much sturdier and less apt to become disconnected. We liked the overall
ergonomics of the phone, the use of open standards, the built-in Web
interface, and of course the excellent voice quality. TMC Labs would not
hesitate to recommend the snom 100 and snom 200 VoIP phones.
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