What Exactly Is a Microsoft Lync Phone?
By Gary Audin
The enterprise will probably have Lync in its Microsoft portfolio, using it for its messaging and presence capabilities. Lync has matured enough to add the voice application to the Lync network. Although there are software clients for voice, the desktop phone is still preferred in many situations.
Selecting the best Lync phone is not a trivial decision. There are many IP phones on the market; some work with proprietary signaling protocols while others work with standards like H.323 or SIP. Obtaining the most value from a Microsoft Lync implementation requires a Lync interoperable phone for accessing the functions and features of Lync. Microsoft itself does not manufacture IP phones, so a third-party phone must be fully interoperable with Lync.
Why a Desktop Phone?
A desktop phone is always on. That's not true for PCs, laptops, or tablets, which can hibernate when idled too long. From a financial viewpoint, desktop phones provide a much better ROI since they last for up to 10 years compared with 2 to 3 years for cell phones, tablets, and PCs, and only up to only one year for headsets. Desktop phones support multiline capability easily and have directly accessible buttons for most important functions. Desktop phones are required in schools, elevators, hotel pools, and common area in businesses. They are required to satisfy fire and safety codes.
The Lync IP Phone Definition
A phone that works with Lync must be able to operate over an IP network. Lync phones are NOT designed to connect to legacy analog PBXs or connect to the PSTN. They can connect via SIP to a PBX. A Lync phone can best be described as:
• An IP phone
• Using the Session Initiation Protocol (SIP) for signaling
• Transmitting SIP over TCP, although Lync-qualified IP phones use UDP
• Operating with the RTAudio, G.711 and other standard codecs like G.722
• Connecting to an Ethernet LAN or USB port on a PC
• Working under the control of a server running Microsoft Lync Server 2013 or 2010 Enterprise Voice edition
What is Microsoft Lync Server Software?
Microsoft Lync is a unified communications server software platform. Lync connects compatible devices running Windows and other operating systems including mobile devices. Lync provides a single-client experience for presence, instant messaging (IM), voice, video, and Web conferencing both within the organization and externally.
Enterprise Voice is the voice services offering in Lync Server used with Lync IP phones. It delivers a voice option to enhance or replace traditional PBX systems. Lync Server uses the address books maintained by Microsoft Exchange Server and integrates with Lync features including rich presence, IM, collaboration, and meetings. Lync Server was previously called Office Communication Server (OCS), which evolved from Live Communications Server (LCS). Later this year, Lync users will be able to connect to anyone on Skype (which Microsoft owns), enabling communication with millions of people worldwide.
Microsoft Lync Server 2013 Enterprise Voice
Lync Server 2013 Enterprise Voice offers a number of new features. It is backward compatible with products qualified for Lync Server 2010 and Microsoft Office Communications Server 2007 R2, excluding the new Lync features. Most phone firmware is backward compatible with older versions.
What about Other IP Phones?
All IP phones, including Lync phones, can connect to an Ethernet LAN. IP phones may also connect to a USB port on a computer. In either case, the IP phones are powered via Power over Ethernet (PoE) over the LAN or USB power. Another option: Some IP phones can be powered by an external AC adapter.
Most modern IP phones use SIP for signaling. Most SIP phones operate over UDP. Lync signaling also uses SIP, but the SIP packets are carried over TCP.
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Nearly all IP phones support at least two voice codec standards, G.711 and G.729. They may also support wideband, high definition voice codecs including G.722, G.723.1, G.726, GSM 6.10, and iLBC. Lync phones can support the Microsoft codec RTAudio. RTAudio stands for Real-time Audio. It is proprietary to Microsoft, not a standard. It is a voice
codec designed for real-time two-way VoIP communications. RTAudio is the preferred Microsoft audio codec and is the default codec for Microsoft's Lync platforms.
Desktop Phones for Lync: Two Classes
Microsoft has developed two categories for Lync phones: IP Phones Optimized for Lync or Qualified IP Phones Tested and Qualified for Lync. The qualification program supports partner-developed and -designed IP phones to ensure they interoperate with Lync based on publicly available Windows Protocols (WSPP) and Microsoft Office Protocols.
• Optimized Lync IP phones run the Microsoft Lync Phone Edition software on the phone and support PBX functions, access to calendar and contacts, conferencing, and extended functions when connected to the PC, and integrated security and manageability. Optimized phones are designed specifically for Lync. These phones have been firmware tested with the Lync Phone Edition software. These phones only work within a Lync environment and are limited to the functionality provided by Microsoft.
• Compatible and Qualified for Lync are IP phones containing firmware tested with the phone manufacturer's software. Compatible IP phones do not require gateways for interoperability. Qualified phones support core Lync features and also allow for customized telephony features and third-party voice applications. They are tested and qualified by Microsoft to provide direct connectivity, core call functionality, presence awareness, and server management and provisioning.
Both classes of Lync phones, Optimized for Lync and Compatible and Qualified for Lync, feature a range of phone models designed to meet specific business needs, including a basic desk phone, common area phone, or conference room phone.
Lync Phone Edition for Optimized Devices
Lync Phone Edition is part of the software that comes with Lync Server 2013 and 2010. This software runs on qualified devices (Optimized Lync IP phones). The software provides traditional and advanced telephony features, security, and manageability. Lync Phone Edition works with Lync Server 2013 and Lync Server 2010 in the same way.
Some phone manufacturers with Lync compatible and qualified phones have their own Lync firmware for their phones. This is usually an optional software module enabling them to connect directly and natively to Microsoft Lync. It also combines the advantages of open standards-based IP telephony by using the SIP protocol to seamlessly integrate with Lync and any other SIP based IP PBX in parallel.
Gary Audin is the president of Delphi Inc. email@example.com, an independent communications consultancy. This article is the first in a series of guest-authored educational blog posts (at snomchannel.com) on using Microsoft Lync with Enterprise Voice. Future posts to the site will feature deeper dives into deployment and use scenarios of Microsoft Lync with snom IP desktop phones.