AudioCodes 420HD and Lync Address Book Service

After January 2014 firmware release, the Audiocodes 420HD got a nice feature — Lync Address Book service query. Before this update we could add a LDAP as Corporate Directory source, but this was based on Active Directory information and not on Lync Address Book service. Also, we couldn’t see the user presence information on searched contact.

In UC_2.0.3.16 firmware version, a new option was added as “Corporate Directory” source — Lync Contacts. This means that we can use Address Book service to search Lync Contacts on AudioCodes 420HD phones.



To configure Lync Contacts as Corporate Directory source we need to access the phone web interface and then go to Configuration -> Advanced Applications -> Contacts:


Let’s use this cool feature, first by accessing the Directory List using the open book on the main screen:


Then by selecting Corporate Directory:


Use the numeric keypad as search input:


As we can see, users with “da” within the name will be showed with their presence status. The full moon icon on its left indicates that the user is Available; the half filled circle indicates that the user is Away/Busy.

This is a nice feature for those who use AudioCodes phones with Lync Server. I still wish to see Better Together over Ethernet feature on these phones.

AudioCodes 420HD – Failed to validate server

AudioCodes 420HD can be a good replacement for Lync Phone Editions, at least regarding its price. However, don’t expect to have all the features that exist in the Lync Phone Editions. In addition, AudioCodes has already promised to enable Better Together over Ethernet to 420HD, 430HD and 440HD in a future firmware release.

The provisioning of these phones is different, but I strongly recommend that you prepare the same requirements as needed by Lync Phone Edition Phones. Jeff Schertz has a great article on how to configure the requirements:

Configuring Lync Server for Phone Edition Devices

Now that we have configured the requirements, let’s go back to the phone. 420HD supports two methods of authentication, one by using Sign-in address:


Another by using Phone Extension:


To change the Sign-in method, we use the option Switch sign-in method that is available in the Sign in menu:


After setting the method and trying to sign in, I got the error saying that Failed to validate server:


In this case, I thought that it had to do with certificates and that the phone didn’t trust Lync Server certificate issued by the internal CA.

The phone firmware version was updated to


We can install the internal root CA in the phone. The first step is to go to Configuration>Security>Security:


In this page we can see that the CA certificate is empty:


To load the certificate, select Choose File, then select the proper certificate (*.cer). After selecting we need to Load the certificate.


Almost done. Just reboot the phone and try to sign in again: