High-fidelity VoIP

Polycom's mix of IP phones hits the high notes

Not so long ago, I wrote an article on Asterisk and open source VoIP in general. In my discussion with Mark Spencer, the founder of Digium and the Asterisk project, he recommended Polycom as the phone vendor he would choose for an Asterisk deployment. In the same article, I profiled Summer Bay Resorts, which runs Asterisk across multiple call centers and hundreds of agents, all with Polycom phones. You might think Polycom is onto something.

[ Polycom'sIP phones were selected to receive InfoWorld's Technology of the Year award. See the slideshow of all the winners in the networking category. ]

Polycom is known to most as the producer of the “boomerang” conference room speakerphone. With their instantly recognizable tricorner shape, these phones can be found in nearly every conference room in the United States. The rest of the product line hasn’t received the same level of attention, but my time with the Polycom SoundPoint IP 650 executive phones shows that they deserve it. In addition to its wired sets, Polycom recently acquired SpectraLink and its VoIP Wi-Fi technology. I tested several SpectraLink Wi-Fi sets, a few IP 650 sets, and yes, the VoIP version of that ubiquitous speakerphone.

All three phones were tested with Asterisk running under Trixbox 2.0, and used with a variety of trunks, from ATA (Analog Telephone Adapter) bridges to the PSTN to pure SIP trunks served via BroadVoice. As with all VoIP phone tests, I tend to use my Cisco 7970 phone as the touchstone, since it’s arguably the most advanced IP phone available on the market today.

SoundPoint IP 650 SIP desk phone

The IP 650 phone is Polycom’s flagship model. Boasting a large paper-white display, six line buttons, a speakerphone, headset jack, and SIP functionality, the IP 650 is meant for the executive desk. It also features a direct-in power source, PoE, CDP (Cisco Discovery Protocol), and a 10/100 PC switchport with 802.1q trunking.

Setup and configuration of the IP 650, as for the rest of Polycom’s SIP line, uses an FTP, TFTP (Trivial FTP), or HTTP server to deliver configuration files to each phone based on the phone’s MAC (media access control) address. This means you can feed global configuration files to every phone simply by listing the file name within the appropriate XML tag in the phone-specific configuration file. This method permits a truly modular configuration platform to be developed and delivered, although as with any XML-based configuration, the files can get somewhat unwieldy when they reach a certain size.

The basis of the phone’s configuration and application set is the Polycom firmware release. The phones will not function without a valid app set that is loaded on boot, and firmware upgrades are performed in a similar fashion: If the phone boots and one of the configuration files references a newer release than the phone is currently using, the new release is pulled down and loaded into the phone’s flash.

Configuring each phone for use with Asterisk was a snap; all I had to do was change a few lines in the phone-specific configuration to note the Asterisk server address and assign extension, extension secret, and the text to display on the phone itself. The rest of the phone’s configuration is handled via DHCP (Dynamic Host Configuration Protocol) or by hard-coding the parameters within the phone itself. Using DHCP to deliver the required data is very simple, requiring that a few options be defined with the IP address of the FTP or TFTP server. As long as the required files exist on that server, all is well.

Once the phone is operational, you have a wide variety of configuration and status options to choose from. With the admin code, it’s even possible to get live network, CPU, and memory utilization graphs to display right on the phone, and the phone’s full configuration is available during normal operation and at boot time. Further, a Web interface for each phone lets you make changes to the configuration, but surprisingly doesn’t offer the option to reset or reboot the phone.

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As far as call quality goes, the IP 650 is simply stellar. In fact, this is one of the best-sounding VoIP handsets I’ve ever used, with any codec. The noise cancellation is superb, and at times a little unsettling because the silence is so silent you begin to wonder if the call has been disconnected. On the downside, the default ring tones are annoying; only the lone sampled ring isn’t terrible. There are slots for many more custom sampled ring tones though, so anything you can distill into a sample can be used. The message waiting light on the IP 650 works perfectly with Asterisk, as does the messaging menu on the LCD screen. (Here I might point out that my Cisco 7970 still doesn’t properly handle a SIP message waiting signal.) Also, the IP 650 handled the long-cable-run PoE test better than any other phone I’ve tried, including the Cisco 7960. Whereas the 7960 would power up but eventually flake out, the IP 650 works flawlessly.

The IP 650 can also run custom applications to deliver corporate directories, interactive services, and the like right to the phone, using the built-in XHTML browser. The browser is relatively finicky though, and warnings in the documentation tell tales of phones rebooting and locking up when parsing invalid XHTML syntax.

The Polycom SoundPoint IP 650 is a solid, well-rounded VoIP handset that will not disappoint. At $449 MSRP, it’s also cheaper than many high-end VoIP phones.

SoundStation IP 4000 SIP conference phone

The SoundStation IP 4000 speakerphone shares much with its analog brethren, including the distinctive boomerang shape and optional outboard microphone pods, but inside it’s a whole new ballgame. The IP 4000 runs the same SIP code as the IP 650 and others in the Polycom line, so the options are standard and the configuration process is essentially the same. A few differences belie the fact that the IP 4000 is a slightly older device than the IP 650 sets, however. These are small things, such as different DHCP option defaults and option patterns, but they can be puzzling when trying to figure out why the phone isn’t booting properly.

The IP 4000 I received was running a much older 1.6.2 version of the Polycom firmware, versus the current 2.1.1 version, and upgrading it wasn't as automatic as it should be, assuming that the phone boots and locates the boot server properly. The problem was that the IP 4000's default settings for the DHCP server option were different than those in the newer phones. Once I modified these settings to match the later models, the phone booted, updated its firmware, and popped online, ready to go.

The IP 4000 has the same paper-white LCD display as the IP 650, albeit much smaller. It’s large enough to do basic navigation and configuration and gives the phone a very cutting-edge look. Although the firmware is the same, the phone is obviously far different than the handset phones. It does not really use PoE as in the 802.3af standard; it uses its own form of PoE with the included outboard injector. The injector is powered by a 19-volt, 1-amp power brick that delivers power to the IP 4000 via the included 20-foot heavy-duty Ethernet cable. The injector also houses the Ethernet connection, so it’s possible to bury the injector and power supply in a distant corner or under a conference table and link to the IP 4000 with the 20-foot cable, reducing cabling mess. The IP 4000 can also drive two outboard microphone pods for extended reach.

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Call quality on the IP 4000 is superb. I ran it in a mix of environments, from very quiet offices to a noisy lab with lots of ambient noise. Talking to folks on land lines and cell phones, I found that the IP 4000's noise cancellation could overcome high levels of external noise and deliver reasonably crisp audio. In fact, it performed quite well even when placed directly between the speaker and a loud air conditioner. At $1,099 MSRP, it’s not a cheap solution, but it’s arguably the best of breed. The heritage of the IP 4000 is full of top performers, and this edition is no different.

SpectraLink NetLink e340 wireless handset

There are many Wi-Fi VoIP handsets on the market now, running the gamut from the low-end consumer devices from Linksys and ZyXel to high-end corporate devices from Cisco and SpectraLink. These phones generally follow the same basic configuration path as their wired counterparts but require more device-specific configuration to allow them to gain access to the network, such as specifying the encryption type, ESSID (extended service set ID), and passwords. Generally, they’re also stand-alone units. The SpectraLink e340 fits the former generalization, but not the latter, as it works with a SpectraLink Voice Priority (SVP) server and supported access points to ensure good voice quality.

The handsets are sleek, with a small LCD screen, a few multifunction soft buttons, and a charging base. Initial configuration of the phones is handled locally, and the phones can be assigned static IP addresses or get them from a DHCP server. In addition to the normal network configuration, you must also enter the IP address of an SVP server. The SVP server is a proxy server for the phones, acting as an intermediary between the SIP PBX and the phone itself.

The SVP server is an odd box that doesn’t conform to any common IT hardware standard -- it won’t fit nicely in a rack, for instance. It runs embedded Linux, and it has only a single tip-and-ring power connection and a single network connection. When a handset boots and contacts the SVP server, the SVP server then connects to the SIP server using another dedicated IP address. This means that each handset requires two IP addresses: one for the handset itself and another for the proxy connection to the PBX. From the PBX point of view, the extension is on an IP assigned to the SVP server, not the handset. This allows the SVP server to handle a variety of QoS tasks. Working with compatible access points, it pushes VoIP traffic to and from the handset to the top of the queue, ensuring that the latency-sensitive packets are delivered in a timely fashion. This results in better call quality and assists in AP roaming functions. The mechanism is a bit ungainly, but it serves a useful purpose. Further, multiple SVP servers can be configured in a redundant fashion.

Call quality on the e340 is good, assuming that the unit is reasonably close to an access point. Drifting further from the AP can result in transmitted voice taking on a “Donald Duck” tone while received audio is still clear and crisp. I also noted that the handsets will hang onto a distant AP longer than they should when another AP is closer. And the e340s are quirky to use. The soft buttons are not only very small, but require significant pressure to trigger. That said, my inclement weather test (basically, leaving a handset out in the rain overnight) resulted in some misting of the LCD screen, but no other ill effects. This certainly isn’t a recommended use of the phones, but it’s nice to know that a little water won’t necessarily kill a handset outright.

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Battery life is good. I conducted conversations lasting several hours with these phones without any problems. Also, they don’t get nearly as hot during normal operation as some other Wi-Fi VoIP handsets, which is a definite plus. A hot phone is not conducive to normal conversation. The e340 does have a standard minijack at the bottom for a headset, though I did note some quality loss when using a Plantronics headset. And try as I might, I couldn’t get the message waiting indicator to trigger on the e340. It’s represented as an icon on the LCD screen, but it doesn’t seem to work with Asterisk.

I’ve tested and used a variety of Wi-Fi VoIP handsets, and the SpectraLink NetLink e340 is right up there in terms of overall quality, ruggedness, and performance. I found a few minor annoyances and quirks, such as the difficult buttons and odd SVP server footprint and dual-IP scheme, but overall it’s a worthy product.

There’s still plenty of room to grow in this space, and as of yet, I haven’t found the truly perfect VoIP phone. Given that VoIP rollouts require a variety of phone types to meet needs throughout the enterprise, standardizing on a single phone vendor is really the only way to go. It means less hassle, easier configuration, and smoother implementation. Collectively, these units show that Polycom is serious about VoIP and SIP telephony. The Polycom line has a little something for everyone, including lower-end handsets that I didn’t test for this article. Especially in an Asterisk environment, Polycom phones are clear winners.

InfoWorld Scorecard
Management (20.0%)
Value (10.0%)
Voice quality (25.0%)
Setup (20.0%)
Ease of use (25.0%)
Overall Score (100%)
Polycom SoundPoint IP 650 8.0 9.0 9.0 9.0 9.0 8.8
Polycom SoundStation IP 4000 8.0 8.0 9.0 9.0 9.0 8.7
SpectraLink NetLink e340 7.0 8.0 8.0 7.0 7.0 7.4