Friday, September 2, 2011

When I am busy I am busy and do not disturb me!

Lync handle the concept of busy differently than many traditional IP-PBX systems. Is it better or not? I do not personally know and I guess that it largely is a matter of taste and personal preference.

When busy in a call in Lync you could still get notifications popping up as a toast on your computer screen, not to intrusive and could easily be handled by most users. But if you also have parallel ringing configured to your cell phone it would also start to ring while you’re in a call, not to nice...

Another scenario where the Lync version of busy might fall short would be in a PBX integrated environment and where you have a serial call list, e.g. call first my PBX phone and then my Lync client and if I do not answer send the caller to my voice mail box. Now if Lync did not hand back a busy tone to the PBX you could end up in a scenario where you are busy on the phone in Lync, another important customer calls and he will not even reach your voicemail box. Hmm...

So we can see that in some environments there is a need for Lync to adapt to an old-fashioned way of handling busy.

Enter the Busy-on-busy software from the good people at Unify Square.

I have tested this little piece of software and it works like a charm! It is easy to install and it is easy to configure the system user-by-user as to if they are going to have busy-on-busy or not.

To install, you simply run a setup.msi on all the Lync front-ends, and the register the software:

C:\Program Files\Unify Square BusyOnBusy>BusyOnBusy.exe /register

Copyright © Unify Square 2011

Registering the BusyOnBusy Server Application.....
Successfully registered the BusyOnBusy server application

Then you simply use the .exe file with a sip address to configure which users that should get a busy tone.

C:\Program Files\Unify Square BusyOnBusy>BusyOnBusy.exe /multiplecalls:block /

Copyright © Unify Square 2011

Certificate SerialNumber is: 62C85547000000000005
Configuring SipUri:, Multiplecalls: block
Configuration for was modified.

Looking at the illustration above we can discuss three scenarios which will be different if the user "Mattias Kressmark" have busy-on-busy turned on.

1. An external call to a PBX-homed DID number which is configured with a serial call list. In this case the incoming call would ring the PBX phone for x number of seconds, move on to the Lync "extension", then get a busy tone by the busy-on-busy tool, and then go to the voicemail system connected to the PBX.

2. An external call comes in and Mattias Kressmark is not answering anywhere, then the caller would end up in the voicemail box. (Yes, I do know about Exchange UM but just because we have two call managers we do not want two voicemail systems as well.)

3. An internal user - Isabella - calls Mattias who is in another call and she will then see the following message in the Lync client:


  1. Do you know the colima Cerebro BusyOnBusy?

  2. Yes, I heard about it - and there is even a free script out there: