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Polycom Soundpoint 331

by OnSIP

OnSIP's review of the Soundpoint IP 331, Polycom's 2-line entry level phone.

Published: August 18, 2009


OnSIP Testing:star_orange_24star_orange_24star_orange_24star_orange_24star_orange_24
Voice Quality:star_orange_24star_orange_24star_orange_24star_orange_24star_gray_24
Ease of Use:star_orange_24star_orange_24star_orange_24star_gray_24star_gray_24

Quick Specs

  • 102x33 pixel graphical display LCD
  • 15 dedicated hard keys, 3 context sensitive soft keys
  • Dual-port 10/100 Ethernet switch


  • Quality entry level product


  • Lack of support for HD Voice
  • Small LCD

Note: The SoundPoint IP 331 was discontinued as of September 30, 2016.

The Soundpoint 331, Polycom’s new desktop phone, is a direct replacement for the Soundpoint 330, the brand’s entry-level IP phone. The two phones are identical except that the 331 has additional memory to support future feature enhancing SIP software upgrades expected in late 2010. According to 888voipstore, the Soundpoint IP 331 is a “cost-effective solution for cubicle workers as well as call center operators who use a ‘hard’ phone in conjunction with a ‘soft’ client running on the PC”.

The phone features a dual-port 10/100 Ethernet switch for LAN and PC connection as well as two lines, each of which can support up to two calls. It comes with a full-duplex IEEE 1329 Type 1-compliant speakerphone and Polycom’s own “Acoustic Clarity Technology”.

The phone also features a 102x33 pixel LCD display UI where users can access traditional business telephony features such as call holding, park, pick-up, transfer, and three way local conferencing. More advanced capabilities include shared call/bridged line appearance, support of XHTML applications, and ‘distinctive call treatment’.

First Impressions

Our initial impression of the 331 was that it was a no-frills business telephone, probably designed specifically for someone who won’t spend more than a couple of hours on the phone per week. It does not come with as many ‘dedicated keys’ as some of the higher end and more expensive Polycom Soundpoint IP phones, so users won’t be able to access applications or transfer and redial with the push of a button. The 331 does not feature High Definition Voice, and the 102x33 pixel LCD UI is small. On the plus side, the phone is one of the better-looking models we’ve encountered. The sleek design and coloring gives the 331 a modern and professional look that would nicely compliment any business environment.

Phone Configuration

Configuring the IP 331 Soundpoint is quick and easy. Resources for Polycom phones can be found in the OnSIP Knowledgebase. One minor annoyance with configuring the 331 is that the phone reboots every time a change is made. Changes to the configuration settings cannot be made while the phone is rebooting so we would suggest inputting all the required information at once. The wait time for each reboot is around 2-3 minutes.

Junction Networks Testing

At Junction Networks, we put each of the phones we use through a multi-step interoperability test in which we put the phones through 30 test cases. An example of a test case would be the following:

“Test phone calls phone B
B picks up
B puts Test phone on hold
B calls phone C
C picks up
B transfers test phone to C

Call must be transferred correctly to C. B must be released correctly after the transfer. When C picks up, audio must work in both ways between test phone and C. When test phone is on hold, there is no audio between it and phone B.

We are pleased to announce that the Soundpoint 331 passed each case.

Phone Voice Quality

Polycom has been introducing phone models which support High-Definition voice to phase out the equivalent ‘narrowband’ phones so that eventually all its lines will support wideband(HD) and be backwards compatible with narrowband. To get an idea of the difference between HD voice and regular ‘narrowband’, one can imagine narrowband as AM radio, and HD as CD-quality stereo. We have been spoiled for a while now with the great sound quality delivered on the Polycom IP Phones such as the 550 and 650 which feature wideband audio. The difference is instantly noticeable as higher registry sounds are much cleaner with HD Voice. HD voice also generates frequencies at the high end of human speech that narrowband tends to cut off, meaning you will no longer have to ask if the person on the other line said “fig” or “pig”. For what its worth, the sound quality of the Soundpoint 331 is good. The phone certainly will not make users feel like they’re seated across from each other in the same room, but it also won’t disappoint. Polycom is well known for their speakerphone quality and this phone is no exception. Again, however, if you can afford it, the speakerphone option would be much better served with HD voice.

There are more user-specifics to consider when evaluating voice quality needs. If you are going to be speaking to a lot of foreign clients, it might be best to have HD voice so you can catch everything. Similarly, HD would make conferencing a much better experience. However, if you don’t expect to be on the phone more than a few times a week, then narrowband might fit your needs and this phone is an excellent entry level option.

If your VoIP phone system service provider does support wideband and you are looking to refresh your gear, however, we would recommend choosing hardware that features HD voice if it is within your budget. While wideband is more of a luxury now than a necessity, more and more companies and service providers are jumping on board. Since most new voice systems are slated for an 8 to 10 year lifespan according to Networkworld, it makes sense to have technology that will get you as far down that path as possible.

Ease of Use

As mentioned earlier, the 102x33 pixel LCD Display UI leaves something to be desired. Since the 331 does not have as many ‘dedicated keys’ as other Polycom models like the 550, many of the features and settings have to be accessed through the small 33 pixel tall display as “soft” keys. Being 33 pixels tall means that the screen can only fit 2 options so users should be prepared to do some scrolling and searching to get to their intended selections. While the LCD menu options for the Soundpoint 331 are the same as the ones for the 550, the smaller display makes desired features and settings feel less accessible. At the same time, most users probably will not have to deal with this minor inconvenience more than a few times, as features such as transferring and conferencing are very accessible via a set of 3 buttons directly under the LCD display. When no call is being made, the buttons lead to messages, recently received calls, and a directory that can be easily configured. During a call, the buttons change to ‘end call’, ‘transfer’ and ‘conference’. Finally, when users have incoming calls, the buttons change to ‘ignore’, ‘answer’ and ‘more’, which leads to ‘new call’ and ‘reject’.

Final Thoughts

We recommend this phone to any business on a tight budget. As an entry-level phone, the Soundpoint IP 331 is a quality product from Polycom and would be a good fit in any situation that does not require high volume calling. However, the lack of support for HD Voice leaves us wanting more. If you can afford it, we would recommend a higher end model from Polycom with HD Voice.

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