Out of the box it can be a bit confusing to tell if your Yealink phone is running the generic SIP firmware or the special Lync/SfB build – and yes, unlike the competitor, they’re different. It can be a little harder if you’re trying to do this remotely and can’t see the phone’s screen. Here are a few clues.

You’re running SIP if…

• The firmware version is anything like “35.73.0.28″ or “35.80.0.95″ (where the leading “35” in this case indicates it’s for a T48G)
• The idle screen looks like this:
  
• The Account/Register tab looks like this (very busy with a pulldown to setup multiple accounts):
  

You’re running the Lync/SfB version if…

• The firmware version is anything like “35.7.0.50″ or “35.8.0.20″ (where the leading “35” in this case indicates it’s for a T48G)
• The Account / Register screen is either of the below, i.e. a lot less ‘busy’ than the equivalent image above:

  

  

• This should be a bit of a giveaway ;-)
  

Ambiguous Clues

As the firmware has evolved, more references to SfB are appearing in the phone’s screen and WebUI:

Ambiguous (but still Lync/SfB)	Lync / SfB version

You’ll need a Lync/SfB licence too

Getting hold of the Lync/SfB firmware isn’t sufficient to convert your lucky eBay purchase from SIP – you’ll also need a licence file. This might have been burnt into the device prior to you receiving it, or it will otherwise arrive as a “License_1234567890.dat” file. Loading that is a straightforward process I’ve documented here.

– G.