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{mospagebreak toctitle= Introduction}

Introduction

ZYXEL VoIP Wi-Fi phone

ZYXEL VoIP Wi-Fi phone
Summary Updated version of SIP-based WLAN phone that still uses 802.11b and supports only WEP security
Update None
Pros • Slimmer design
• Cordless phone comparable range
Cons • 11b will slow down 11g WLANs
• Doesn't support WPA or WPA2
• Unimpressive transmit voice quality

ZyXEL's P2000W v2 is an update of one of the first "consumer" VoIP WiFi phones. Although ZyXEL's marketing material pitches both consumer and corporate buyers, I picture businesses as the real target, with perhaps some individual VoIP junkies coming along for the ride.

It's available from some sources locked to Voiceglo's tglo service, but I requested that my review unit be unlocked so that I could fully explore it.

The "v2" shown above is a bit more compact than the the original (Figure 1) and has more of a squared-off look.

The original P2000W

Figure 1: The original P2000W

It also doesn't include a stand or case, coming only with a largish "travel charger" that plugs into a mini-USB port on the bottom of the phone to charge the removable 3.7V 1350mAh Li-ION battery pack.


Product Details

The handset (Figure 2) made a good initial impression, but after handling it for awhile, I got the impression that the handset wouldn't take kindly to drops only hard surfaces (I didn't verify this via drop tests). In addition to the front panel buttons, there are volume up / down buttons on the left side, along with a headset jack.

The phone in hand

Figure 2: The phone in hand

The four-way rocker switch and two arrow buttons above it are used for most functions. The arrangement worked ok, but I felt that there could have been better separation between the four-way rocker and arrow buttons.

Since the "earpiece" is just a small slit near the top of the phone, I thought it would be difficult to locate. But I actually found it easier to use than the slightly indented ear hole on the Olympia Dualphone. The ringer speaker is on the back of the phone, which is a good thing because the ring tones are very loud, except at the lowest settings. There's also a buzzer which can be used instead of, or in combination with the audible ring.

Like most phones with large screens, the v2's screen gets easily smeared with skin oils. So I found myself constantly having to wipe off the screen. I should also note that the backlighting on the black-on-blue screen is pretty dim and not adjustable, so I found myself squinting at the screen and moving the phone around in low-light conditions. I actually found the screen more readable with bright ambient light.


Inside Story

The v2's FCC ID indicates that ZyXEL OEMs the phone from BCM Communication in Taiwan, which refers to the phone as the WLAN660.

Figure 3 shows that the v2 has a TI TMS320VC5472 at its core. This chip is a dual CPU processor that includes a TMS320C54x-series DSP and an ARM7TDMI RISC MCU. Note that the link above points to the page for the 5471 since there's no page for the 5472, but the parts are most likely very similar. Note also that's a metric tape measure you see in Figure 3.

P2000W v2 internal view

Figure 3: P2000W v2 internal view
(click image to enlarge)

Figure 4 is a close-up of the v2's radio, which is implemented as a plug-in board and based on Conexant PRISM3 chipset (the ISL3871 is single-chip baseband / MAC).

P2000W v2 radio board

Figure 4: P2000W v2 radio board
(click image to enlarge)

The v2's radio section has three weaknesses, which could limit its use in enterprise, if not SOHO use:

  • it is 802.11b only, which means that the phone will cause a throughput hit to 802.11g networks due to the 802.11b protection mechanism that must be employed by 11g networks to accomodate 11b devices
  • it supports only 64 / 128 bit WEP for wireless security and not the more secure WPA or WPA2 mechanisms, or even 802.1x-based authentication
  • it has a relatively low 14.3 dBm / 27 mW maximum transmit power and receive sensitivity (-82 dBm) which can limit its effective range

Finally, although the radio board has mini-connectors for two antennas, Figure 3 shows that only one non-extendable antenna is connected.


In Use

Although you can set the v2 up using its keypad and display, I chose instead to use the keypad, display and built-in Site Survey function (Figure 5) to first get it associated with my wireless router and assigned an IP via DHCP. I could then use its Information > IP Address menu to find the IP and complete the rest of the setup using its web interface. Figure 5, which was taken from the v2's PDF User Manual, shows that the Site Survey displays SSID, signal strength and encryption status.

Site survey

Figure 5: Site survey
(click image to enlarge)

There are actually two levels of web interface: user, which provides access to all settings except for SIP settings; and administrator, which adds access to the SIP settings. The interface takes a few seconds to go between screens, but takes at least 30 seconds between the time you log in and when the first screen comes up. You can restart the phone from the web interface - which I recommend after any programming - but can't log out of the interface. So if you want to change from user to administrator mode, you'll need to quit and restart your browser.

SIP settings
Figure 6: SIP settings
(click image to enlarge)
NAT Traversal settings
Figure 7: NAT Traversal settings
(click image to enlarge)

If you've programmed a SIP device before, you'll be able to find your way around the v2's configuration screens, and I found everything that I needed to get the phone set up and registered with my BroadVoice BYOD account. The phone also supports auto-provisioning via HTTP download and browser-based firmware updating. But if you need to control dial plans or other more advanced SIP settings, you won't find them on the v2.

Figure 6 shows the SIP settings page, and Figure 7 the NAT Traversal settings. The v2 supports Outbound proxy, STUN and Fake WAN address methods of working around problems with NAT routers and the screenshot shows I've selected Outbound Proxy. (Pay no attention to the STUN and Fake WAN settings, since they're just default dummy addresses.)

Phone settings
Figure 8: Phone settings
(click image to enlarge)
Wireless settings
Figure 9: Wireless settings
(click image to enlarge)

Figure 8 provides a peek at the Phone settings screen where you can see that G.711u, G.711a, and G.729 codecs are supported and you can select inband, outband or disable DTMF relaying, and Figure 9 shows what you get for wireless knobs to tweak.

I'm not providing a screenshot for the Network setup screen, since it's pretty straightforward. You can enter settings manually (Static), use DHCP (the default) and there's even a PPPoE mode in case you need to connect the phone directly to a PPPoE connection. I found the last option to be somewhat odd , since I wouldn't want to connect any device directly to an Internet without the benefit of a firewall in front of it!

The phone also supports an internal Phone Book to ease dialing chores and also allows dialing from a list of recent calls. But you can't save entries to the phonebook from the recent call list, nor can you assign more than 10 speed dial numbers to phone book entries.


Bad Connection

Once I got the phone programmed, it successfully registered with my VoIP provider and I made my first call. The call completed just fine, but was basically unintelligible on both ends. I double checked settings and tried again (and again...) but could not make an intelligible call. When I told ZyXEL of my problem, they provided me with a different SIP account so that I could eliminate that variable, but trying the new account didn't resolve the problem.

To make a long story short and condense days of troubleshooting into a bottom line, the problem was caused by a bad phone. The second phone ZyXEL sent was able to successfully associate and work with the Westell 327W wireless router (firmware version: 03.00.63a) that provides my DSL connection and a Linksys WRT54G (original hardware version and firmware version: v2.04.4, Aug. 3, 2004), which didn't work with the first phone. It also worked fine with a ZyXEL G-2000 Plus, which was the only thing I could get to work with the first phone.

I started out with a few test calls, first to an answering machine on my normal VoIP line. I could hear my outgoing message fine, but when I checked the test message I left, it sounded somewhat muffled. I then called a colleague, who also complained of static and "lousy" voice quality, although I could hear him just fine.

In order to get a more objective measure of voice quality, I tried some calls to TestYourVoip.com's Golden Phone, which generally confirmed the results of my subjective tests. The best I got was a MOS score of 4.4 (best possible) when the phone was connected to a ZyXEL G-2000 Plus 802.11g router.

But MOS scores of 4.3 and 4.2 were achieved when I connected via the Linksys WRT54G where packet loss and discards accounted for about 25% of the degradation. My runs with the WEP-enabled Westell 327W were the worst (Figure 10), coming in at 3.7 (with about 50% of the degradation due to packet loss). Thinking the poor result might be due to WEP, I disabled it and tried again, but the results were essentially the same. Note that the largest source of degradation - Codec - is expected and accounts for the difference between the 4.4 "best possible" and 5.0 "perfect" scores.

Golden Phone results - Westell 327W

Figure 10: Golden Phone results - Westell 327W
(click image to enlarge)

I was able to test the phone's range by calling my local telco and slowly working my way through its robo-operator menus and walking around my home. I also ran a continuous ping from a desktop to the phone as a double check for connection drops. I found coverage throughout my two level home to be comparable to what I get with my 900 MHz cordless phones - some spots that require standing in particular positions, but generally ok.

At least all the testing and debugging gave me good information about battery life. I found that a couple of hours of making and receiving short test calls drained the battery to the point where I had to put it on the charger. The good news is that with a few hours of recharge time, the phone was ready to go again.


Closing Thoughts

In all, I wasn't impressed with the P-2000W v2. I'll admit some of this is colored by the frustrating time I spent with the first malfunctioning phone. But even when I got a phone that worked, its performance changed depending on the wireless router that I used it with, and the quality of my transmitted voice never seemed to equal that of the person on the other end of the connection. And lest you think that these problems were due to a busy wireless LAN or poor Internet connection, I can assure you I checked both and found them trouble free with sufficient bandwidth available for the phone to use.

My sense is that the consumer market window for Wi-Fi VoIP phones is pretty much limited to gadget freaks and experimenters, since any cordless phone can be VoIP-enabled simply by plugging it into an ATA. And a big advantage of a Wi-Fi phone - working with, not against, your wireless LAN - can be achieved at considerably less expense by using 900 MHz models which, yes, are still available.

The main market for these devices are mobile users who don't find Skype suitable for their needs and enterprises looking to support mobile users on their VoIP-based company campuses. The competition for the P-2000W v2 here is big dawg Cisco's IP Phone 7920 on the (way) high end at around $600 and UTStarcom's F-1000 that can be found for around $20 cheaper than the v2.

What companies really want, however, are dual-mode Wi-Fi / cellular handsets, which continue to be just around the corner. But I think they'll stay just beyond reach until cellular carriers figure a way to get paid even when traffic is handed off to private wireless VoIP networks.

In the meantime, ZyXEL and other lower-cost WiFi VoIP handset makers need to get with the program and get at least WPA and preferably WPA2 implemented on these devices (Cisco's 7920 already supports WEP, WPA and 802.1x). While owning a VoIP phone by cracking its WEP code may not seem like a big security risk, it's the rest of the WEP "protected" WLAN that's really ripe for the picking. ZyXEL should at least implement 802.1x authentication like the Cisco and UTStarcom phones have, which would provide one more hurdle for a cracker to jump.

And while the phones are back on the design board, let's move them to 802.11g so that they can take advantage of single-chip, improved performance radios that won't cause a throughput hit to 11g WLANs. Hits to WLAN performance and security are simply too much to ask users to pay for the convenience of mobile VoIP.

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