Yealink SIP-T28P

Yealink SIP-T28P

“The quality of a Polycom at the price point of a Grandstream.”

I’ve heard Yealink phones described to me like this multiple times. I don’t remember who it was exactly that said it, but the description has since stuck in my head. It could’ve even been a Yealink reseller as the phrase certainly is a catchy way to pitch the brand to a person like myself—someone who is at least somewhat familiar with the established players in the VoIP hardware industry.

This got me thinking. A few years back, ‘quality of a Polycom at the price of a Grandstream’ would’ve meant a lot more. It wasn’t long ago when only a few select VoIP phone manufacturers offered ‘high definition’ audio, crisp backlit LCDs, and some of the extra features you wouldn’t find on a traditional desk phone. If you wanted exceptional audio back then, you got Polycom phones. If staying within your budget was your main prerogative, you probably went with Grandstream. And, if you happened to be one of the few who wanted to do video calling via desk phone, there were only a handful of options available.

Nowadays the product lines of competing VoIP manufacturers aren’t as different. Codec support and feature sets are pretty identical across the spectrum of brands. For example, nearly every VoIP phone I’ve tried and tested in the last year supports G.722 wideband audio. What we’re seeing now is a homogenization of product offerings from VoIP hardware manufacturers, which is to be expected in this maturing market.

It’s easy to say phone A is ‘better’ than phone B when phone A has better audio quality, a color backlit LCD and a built-in back scratcher, and phone B does not. When the two phones have incredibly similar feature sets, however, a lot of it comes down to personal preference.

Okay, enough rambling. Yealink phones are supposedly the quality of a Polycom, with the price point of a Grandstream according to sources I do not recall at this moment. ‘Too long; Didn’t Read’ Version of the above: I get the sentiment, even if I don’t completely agree with the implications.

The Yealink SIP-T28P is a PoE enabled enterprise desk phone that supports up to 6 simultaneous SIP account registrations. The phone has a 320 x 160 pixel backlit LCD, 48 keys in total including 10 programmable ‘shortcut’ keys, and support for BLF and SMS. It features G.722 wideband audio, with the marketing materials on the company website suggesting that the hardware (handset and speaker) is also ‘HD’. Headset (RJ45) and extension module jacks can be found underneath the device. We did some digging around to see just how affordable the T28Ps are. The list price of $189 is already very reasonable for a 6-line enterprise desk phone, but you can find it for even less ($110) on certain online retailers like Telephony Depot.

Phone Configuration

The following will be a quick guide to manually setting up the Yealink T28P with OnSIP. The steps shown here should also work (more or less) if you’re using another provider.

These instructions assume your phone has successfully booted and completed network configuration including obtaining valid IP addresses for itself, an IP gateway and DNS servers either via DCHP, manual or other means (refer to your phone's documentation) and that your phone is running with factory defaults.

You will need your SIP credentials. You can find them in your OnSIP admin page under ‘users’. The information you’re looking for should look a little something like this:

Next, you will need the IP address of the phone to access the web admin portal. Select the ‘menu’ soft key, and go into ‘1. Status’. The IP address should be on the first line displayed.

Type your IP address into your Internet browser window. You will be asked for a username and password. Default is ‘admin’/’admin’.

The first view in the web admin portal shows you your phone status. Note your phone’s firmware version, as you may need to update it. At the time of this review, we are running version 2.60.0.120. To set up a SIP account, click on ‘Account’ in the top navigation bar.

Enter your SIP credentials as follows in the empty fields on this view.

  • Account: Account 1
  • Label: Your choice
  • Display name: Your choice
  • Register name: Auth Username
  • User Name: Username
  • Password: SIP Password
  • SIP Server: Proxy/Domain
  • Outbound Proxy Server: sip.onsip.com

Select ‘codecs’ to prioritize your audio codecs. You won’t need to go into ‘Advanced’ to set up a SIP account, but you may want to explore the further customization options there later on. Repeat the above steps as necessary if you’re setting up multiple SIP accounts.

The Yealink web portal lets you tweak almost every setting imaginable. Just click on ‘Phone’ in the top navigation bar and you’ll see what I mean. The ‘Preference’ and ‘Features’ views both have dozens of options you can customize. Upload ringtones, set your backlight brightness, choose who you want calls forwarded to when you don’t answer, or upload a custom logo to display on your phone’s background. It’s all there if you do a bit of digging. To set up the 10 customizable LED keys, select the ‘DSS key’ view. The 10 keys on the right side of the phone are called ‘Memory keys’, and there’s plenty you can do with them. See the image below.

Note from the image that you can also customize the function of your 6 line keys, 4 soft keys and even some of the hard keys on the phone. Don’t like that pressing the up arrow on your phone’s navigation wheel takes you to your local call history when you’re on the home screen? It’s easy to change. Now that’s customization you don’t see built into every phone.

Changes made in the Yealink web admin portal are pushed to the phone nearly instantly. No reboots necessary.

JN Testing

At Junction Networks, we put each of the phones we use through a multi-step interoperability test in which we apply ~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’re happy to report that the Yealink T28P passed our interoperability tests with no issues. Note that this phone is also Broadsoft/Avaya/Asterisk validated.

Voice Quality

As mentioned earlier in this write-up, the Yealink T28P does do ‘HD voice’ via the G.722 wideband audio codec. Keep in mind that you will only get HD quality audio when the call you’re on does not traverse the public switched telephone network (PSTN). For OnSIP customers, this means extension-to-extension calls, calls to or from other SIP phones on the Internet, and conferencing.

It’s not quite the HD calling experience you get when you’re on a Polycom, but the overall voice quality from the handset is still quite good. It just doesn’t sound as crisp, and I never really felt like the person on the other end of the line was sitting right next to me like I often do when I’m on a Polycom.

The speakerphone also does not disappoint. Again, it’s not quite on par with Polycom speakerphones (arguably the best in the industry) as callers on the other end sometimes reported white noise, but it’s still above average.

Ease of Use

You won’t find anything too out of the ordinary when you’re using the T28P. The hard key button layout is very similar to what you’ve seen a dozen times on other IP phones. You have your standard numpad on the left-hand side, a navigation wheel and volume keys in the middle, followed by your call handling keys and your 10 LED programmable keys on the right-hand side. Above this is the phone’s 320x160 pixel backlit LCD, which is accompanied by 4 context sensitive soft keys and 6 programmable line keys. Up to 4 menu items fit on the screen at once, which makes navigating through phone menus painless.

As we mentioned in the Phone Config section of this write up, what sets the Yealink T28P apart from many phones we’ve tested is the fact that you can customize the function of nearly every button. You can alter the layout and default function of the context sensitive keys, make line keys into call handling shortcuts, and even change the function of clearly labeled hard keys. If for some reason you want to turn the conference button into a toggle for DND (not sure why you would want to), you can do that on this phone.

You will not be able to juggle calls using one SIP account (or start a second call, for that matter) without first doing a little tweaking in the web admin portal. By default, each of the line keys corresponds to a different SIP account, even if you haven’t set up multiple accounts. If you press the second line key and you don’t have it configured, you will get the message, “Invalid Account”. One way of solving this is by going into the web admin portal, clicking on the line key customization field (Phone > DSS Key > Line Key), and setting a line key to line type ‘auto’. This creates a second line instance of your first SIP account. Now if you want to start a second call, simply click on the ‘auto’ line. This will automatically put your first caller on hold and allow you to dial a new number using the same account.

Have you had any experience with Yealink? How do you think they measure up to Polycom or Grandstream? Let us know in the comments section below.