Unified Communications

Lync Roundup: What Microsoft Lync Partners Are Offering and Why

By Paula Bernier, Executive Editor, TMC  |  January 16, 2014

It’s been five years since the release of Microsoft OCS and three years since Microsoft renamed the product Lync. This solution is noteworthy not only because of the range of unified communications functionality it offers, but also because it comes from Microsoft, which packages the Lync client with the Office suite.

Mike Storella, COO at snom, explains that the Microsoft strategy in the beginning was just about asking enterprises to try Lync for chat, interactive content sharing, multi-party meetings, video, and to have shared directories across their home, mobile and office phones.

Then Lync 2010 added E-911 support and other new features, making it a viable alternative to the PBX. Early on, some folks questioned whether Lync would really be a viable PBX alternative, but as Alan Percy, director of market development at AudioCodes, tells INTERNET TELEPHONY: “Businesses are definitely doing it. There’s a gazillion case studies of companies that are doing it.”

Here is a snapshot of some of the Lync partners and what they’re offering to make Lync even better and more usable.

Aastra (News - Alert)


The Aastra 6725ip is a full-featured IP phone optimized for use with Microsoft Lync. Aastra claims that the 6725ip provides the best Lync phone feature set available, including support of Microsoft’s “Better Together” desktop link, allowing PC desktop control of phone calling features such as transfer, hold, call park, conferencing and click-to-dial. The Aastra 6725ip also features a color 3.5-inch LCD screen; a unified communications presence icon providing direct access to features and presence indications in Lync; exceptional voice quality provided through the use of Microsoft audio codecs on both the handset and speakerphone; embedded Microsoft Lync 2010 Phone Edition Software; dual gigabit Ethernet ports; USB interfaces; and standalone IP phone operation.


The Aastra 6721ip is an entry-level standalone IP phone, also optimized for use with Microsoft Lync. Aastra explains that the 6721ip provides a lower cost option for users who require the benefits of a true IP phone, including dual gigabit Ethernet ports and message waiting light indicator – but do not require the full UC desktop integration capabilities of the Aastra 6725ip. The Aastra 6721ip is an ideal selection for hot-desking applications and common areas, such as lobbies and meeting rooms. It also has embedded Microsoft Lync 2010 Phone Edition Software and?integrated PoE support.

Aruba Networks


Aruba Networks delivers the only enterprise Wi-Fi solution that is qualified for use with Microsoft Lync and for interoperability with Microsoft's Lync software-defined networking API.

Aruba controller-based Wi-Fi, when used together with the Microsoft Lync SDN API, ensures that Lync performs at its best with both desktops and mobile devices. Aruba Wi-Fi can deliver the optimal quality of service for all Lync flows, implement call admission control for Lync flows, and monitor and report on UC performance in real time. End-to-end call monitoring that correlates Lync server call information and Wi-Fi statistics makes quick work of root cause failure analysis, according to the company. Organizations can pinpoint where in the network a call failed, identify bottlenecks that limit Lync performance and diagnose device-level issues.

Aruba's Wi-Fi solution includes 802.11n and 802.11ac access points, wireless LAN mobility controllers, switches for AP backhaul, and the AirWave Network Management System for unified management of wired and wireless.



Tight integration of Aspect Unified IP with Microsoft Lync gives agents the power to reach out across the enterprise and connect with the most qualified person to help with a customer's needs, explains Aspect. Agents can easily spot the experts inside the contact center and collaborate by sharing their desktops or files. This means people can address issues more efficiently and effectively, resulting in increased first-contact resolution and an improved customer experience. It also allows agents to collaborate in real time while keeping managers in control over communications, and lets agents and supervisors connect through a unified desktop, making it easier for agents to handle multiple cases.

Aspect Premier Microsoft Lync Support offered by Aspect, meanwhile, helps companies maintain peak performance of their enterprise Lync solution and deliver a consistently optimal user experience. The integrated services deliver 24x7x365 or 8x6 M-F incident support for critical Lync voice application with no restrictions concerning the number of cases opened annually. It also offers an Aspect team of extensively trained and tested Lync experts certified by Microsoft to respond to issues within targeted time frames, including in-process status updates and escalations.



AudioCodes has the One Voice for Microsoft Lync brand, which includes IP phones, gateways, session border controllers, and survivable branch appliances. It also offers Lync call recording compliance, as well as Lync-related services including network voice readiness, for which AudioCodes assesses whether the customer network is ready for the rigors of voice, video, desktop sharing, and other multimedia that Lync supports.

The AudioCodes One Voice for Lync puts all of the company’s voice-based UC hardware, as well as professional services and support, under one umbrella. AudioCodes started with gateways, moved to E-SBCs, then added survivable branch appliances, and recently expanded to its IP phone line. The creation of this suite of products and services is particularly relevant for AudioCodes partners coming from the IT space, according to the company, which explains that these folks are not as experienced in the voice realm, so can use a hand with integration. One Voice for Lync gives IT-centric partners one place to go for all the voice pieces.

Crestron Electronics


The Microsoft Lync Room System: Crestron RL is a comprehensive solution that combines Crestron hardware with Microsoft Lync to bring Lync from the desktop to the conference room. In addition, Crestron RL links to all systems in the room and gives users control of the entire room from the same touch screen. As a result, with just one touch of a button, anyone can walk into a conference room and instantly start a collaboration session; share their desktop with local and remote participants; and view and annotate over Microsoft PowerPoint or interactive whiteboard remotely or locally using the 65-inch touch display(s) supplied. Remote participants can join via Lync on their desktops.

Crestron RL is designed to seamlessly integrate with Crestron DigitalMedia and all other Crestron enterprise control solutions and products to offer a complete room solution. Simply press the RL button to instantly access lighting, shades, thermostats, DigitalMedia, AV presentation, and much more – all from the same touch screen. Crestron RL rooms can be centrally monitored, managed, and controlled using Crestron Fusion software for a complete Enterprise Building Management solution.

The Crestron RL packaged solution includes the Crestron UC Codec for Lync, HD camera, microphone, 65-inch touch display(s), a hi-res 10-inch tabletop touch screen, and more.

CVT (Global) Pty Ltd.


CVT’s Periscope GC for Billing and Enhanced Reporting on Lync recognizes that Lync provides an opportunity to deliver more functionality for customers. Not only does Lync deliver a rich unified communications environment for users, but it coincides with the latest Microsoft technologies in operating system, database and web application development.

Periscope GC takes advantage of these developments to deliver a rich web-based user experience providing well-established telecom reporting features such as on-billing, call cost accounting, and service provider bill import, and extending that further to drive business analytics around the unified communications play. In the Microsoft Lync environment as well as reporting on enterprise voice usage, Periscope GC will also provide insight and reporting on other Lync media usage including application sharing, file sharing, IM and video.

Periscope GC, a qualified Microsoft Lync 2013 solution, is used by customers in all verticals delivering the full range of requirements including more than 100 standard report templates in multi-formats, scheduled reports, exception reports, monitoring dashboards and more.



Dell Software simplifies migrations, ensures availability and maximizes performance while decreasing the management complexity of Microsoft Lync Server. The company says it has proven expertise and many years of experience managing millions of mailboxes and users, and can help prove that Lync and OCS are delivering their intended business results.

The company simplifies and accelerates Office Communications Server and Lync Server migrations with less risk to the budget and business operations and ZeroIMPACT on end users. Dell allows companies to migrate from Lotus Sametime to Microsoft Lync Server or OCS with solutions from Dell Software to help ensure a safe, accurate migration that saves business time and money. Dell Software provides the insights needed to understand the usage and adoption of the Microsoft Lync Server and OCS. By assessing the adoption and usage, organizations ensure that its benefits are fully realized.

Dell Software’s products for these solutions include Migrator for Sametime, which offers in-depth pre-migration assessments, centralized project management and task automation. Because user contacts are migrated with complete accuracy, end users will not need to rebuild or reorganize their contact lists in the new environment because user contacts are migrated with complete accuracy. Dell also provides MessageStats, which reduce the complexity of e-mail and unified Microsoft Exchange reporting and analysis. This solution works across legacy Microsoft Exchange Server and newly implemented platforms, including on-premises Exchange, Office 365 and Lync Server. ActiveRoles Server from Dell simplifies the security and protection of Active Directory to solve security issues and meet compliance requirements. And its Spotlight on Messaging solution allows users to easily perform real-time diagnostics and resolve problems. From a single console, users can manage e-mail, IM, VoIP, mobile, conferencing and more for Microsoft Office Communications Server (OCS)/Lync Server, Microsoft Exchange Server and BlackBerry (News - Alert) Enterprise Server.



GENBAND C20 PSTN Gateway, EXPERiUS Application Server and QUANTiX SBC are all fully qualified by Microsoft under its Unified Communications Open Interoperability Program. All are Certified with Lync 2010.

GENBAND SMART SESSION SIP Trunking solution, meanwhile, enables enterprises and service providers to deploy a Microsoft Lync certified SIP trunk that is secure, adaptive to multiple SIP and IP variants, interoperable with non-Lync premises-based equipment, and enabled with hosted UC services such as GENBAND's SMART OFFICE.

Key benefits of GENBAND and Microsoft Lync Integrated Solution include hosted telephony service integrated to on premises OCS/Lync unified communications; flexibility in interworking with on-premises and hosted Microsoft Lync deployments; secure migration from PRI to Lync certified SIP trunks; centralized session management across Lync and non-Lync environment for advanced telephony and unified communications; seamless signaling, IP protocols, and media normalization between multi-vendor PBX, IVR, and UC environment; improved network resiliency and disaster recovery with multi-site geographic redundancy; better controls to assure QoS and SLA from SIP trunk providers;  consistent user experience with enterprise mobility and federation across multi-vendor environment; and simple integration of new converged UC and multimedia applications with minimal investment and minimal infrastructure change.

The company plans to achieve certifications with Lync 2013 and Office 365 next year for individual products. GENBAND already has performed successful testing of its SBC product with Lync 2013 and has it working in customer deployments.



Customer experience and contact center solutions provider Gensys has achieved Microsoft Lync 2013 qualification and is a member of the Microsoft Lync Independent Software Vendor qualification program.

Companies select Genesys (News - Alert) and Microsoft Lync to leverage the combination of best-of-breed contact center and unified communications solutions, rather than closed proprietary hardware-based solutions. By incorporating multi-channel customer experiences and contact center capabilities from Genesys, Lync customers can seamlessly deliver voice and instant messaging interactions to both their customer service agents and back office employees.

Genesys integrates the real-time presence and availability status of all Lync users, which enables companies to route calls coming into the contact center to any available employee wherever he or she is located – in stores, branch offices, home offices, outsource partners, or any other location. As a result, organizations using both remote employees and contact center agents are able to track the availability of an employee resource beyond the contact center and better direct enquiries based upon the status of any given resource to increase efficiency of service. 



Ingate E-SBCs are fully qualified by Microsoft’s Unified Communications Open Interoperability Program guaranteeing a secure and reliable use of Microsoft Lync applications. Microsoft recommends an E-SBC to provide connectivity and interoperability when connecting the Lync environment to a SIP trunk service.

The Ingate E-SBC resolves interoperability issues between the SIP trunk provider, other on-premises equipment and the Microsoft Lync server, paving the way for a fast, simplified installation. Ingate provides solutions for enterprises and service providers and the Ingate E-SBC products available both in hardware and software versions.

While all of Ingate’s SBCs already are compatible with Lync, it is in the process of getting certified on Lync 2013. It expects to have that certification this quarter.

Interactive Intelligence


Customer Interaction Center, a software solution from Interactive Intelligence,

has passed the UCOIP-Lync Qualification program for direct SIP connection interoperability, and the Lync Server 2013 and 2010 Qualification programs for interoperability with contact center systems.

CIC and Microsoft Lync Server integration provides a feature-rich contact center add-on to Lync enterprise telephony deployments. The combined solution helps mid-size to large enterprises improve collaboration between contact center agents and business users through shared features such as presence management, directory look-up, instant messaging, video, and more.

Key features include a single CIC/Lync directory with integrated real-time presence management and one-click access to multiple communications channels (e.g. IM, video, voice calls, e-mail, faxes, desktop sharing, etc.) for increased productivity and improved collaboration between the contact center and enterprise. In addition, CIC’s open architecture enables customers to deploy Lync-certified third-party endpoint devices so they can use existing infrastructure and equipment for maximum investment protection and increased ROI.



Jabra and Microsoft work as strategic partners to integrate Jabra devices into current and new generations of Microsoft Lync solutions to deliver the ultimate voice collaboration experience. Jabra audio devices that are optimized for Microsoft Lync are tested by Microsoft to offer a rich and integrated voice experience for Microsoft Lync users. The term optimized means that Jabra devices are built to rigorous Microsoft Lync specifications and adhere to the highest standards for voice quality and call control.

When customers buy Lync optimized devices they are guaranteed that their devices will work with Lync. In addition, they are assured that Jabra and Microsoft are aligned for post-sales support or service.

Today, Jabra offers a full portfolio of Lync-optimized devices suitable for different user work styles (mobile, office and desk-centric). Jabra’s Lync-optimized devices ensure the best user experience by combining plug and play capabilities with innovative features, automatic device detection, remote call control and superior wideband audio quality. Those devices include bluetooth headsets for mobile professionals; wireless headsets and speakerphones for office staff; and corded headsets for desk-centric employees.



PhonEX ONE, a software solution from MIND, is a comprehensive, flexible, web-based solution for communications management and control in enterprises that deploy Microsoft Lync Server 2013/2010.

The comprehensive and varying communications media types available with Microsoft Lync Server 2013/2010 means it is important to have the ability to report, monitor, and manage the resources accordingly. Companies that take advantage of the Lync platform want to be able to reduce costs, increase employee productivity, and improve network performance. PhonEX ONE provides intelligent tracking of all calls and supports multiple call types generated by Microsoft Lync Server 2013/2010. This includes reporting on inbound, outbound, and internal calls; trunk-to-trunk calls and SIP trunks; forwarded, conference, and video calls; instant messages; and response groups.

Customers can easily produce customizable reports with drill-down capabilities, including traffic reports to monitor peak loads and bandwidth utilization as well as what if reports to compare alternative carriers and analyze potential cost savings. Other PhonEX ONE features include a dashboard user interface, event log for auditing and tracking system use, scalable architecture to support unlimited sites and extensions, LDAP compliance, easy adjustment to organizational hierarchies, a database structure based on Microsoft SQL Server database, automated reports (e-mail, screen, or saved to file), user-definable report format (in Microsoft Excel and Word, HTML, PDF, and CSV files), capability for multiple languages, currencies, and call detail records, cellular phone reporting, real-time automated alarms, and support for virtual environments.

NetScout Systems Inc.


NetScout’s nGenius Voice | Video Manager is a unified communications performance management solution for UC deployments that has unique integration capabilities for Microsoft Lync deployments. It delivers real-time visibility into the user experience with end-to-end and call signaling and media performance for voice and video sessions. Qualified by Microsoft for both Microsoft Lync Server 2010 and Microsoft Lync Server 2013, the solution automates and simplifies the identification, triaging, investigating, resolution, and reporting of emerging voice and video service performance degradations. The nGenius Voice | Video Manager platform automatically combines performance metrics from Microsoft Lync endpoints with performance metrics generated from packet flow data at key visibility points along the call path, and from critical UC network infrastructure elements.

The nGenius solution provides contextual workflows that enable analysis and troubleshooting capabilities that support both proactive and reactive performance management tasks. This enables IT staff to quickly understand the impact of voice and video application-level service degradation on end user experience, precisely pinpoint root cause, and quickly resolve service quality problems thus reducing mean-time-to-repair.



Patton’s SmartNode VoIP media gateways have been tested and qualified for interoperability with the 2013 version of Lync Communications Server in Microsoft's Unified Communications Open Interoperability Program (UCOIP)

SmartNode eliminates the interoperability obstacles for companies that want to keep their legacy PBXs, phones, speakers, pagers, and fax equipment, existing FXS/FXO POTS service or ISDN BRI/PRI lines when implementing a unified communications solution based on Lync. Enterprises operating otherwise non-compatible voice equipment and telephony network elements ­– including non-certified SIP telephony systems – can use Lync-certified SmartNode VoIP gateways to connect and interoperate with the Lync unified communications server.

By interconnecting Lync software with legacy voice technologies and the PSTN, SmartNode preserves investment in operational equipment while adding such rich benefits as voice-and-data survivability and least-cost call routing – all with the set-it-and-forget-it reliability of SmartNode. The 2013 re-certification assures customers that SmartNode interoperates seamlessly and reliably with Microsoft's UC software.

“When it comes to solving interop challenges, Patton’s history is long and strong,” said Tyler Delin, SmartNode product manager. “Not only with Microsoft and Lync, but in the VoIP industry overall. SmartNode was the world’s first VoIP gateway that could actually get VoIP working in some extra-tricky ISDN environments.”



Plantronics audio devices are optimized to work seamlessly across the Microsoft Lync platform and beyond. The partnership provides simple, highly integrated audio solutions to bring technology and people together and create more productive, efficient and empowered businesses. Contextual Intelligence enables Plantronics audio devices, optimized for Microsoft Lync and Skype (News - Alert), to simplify and ease communications by understanding the user's location and delivering a service that best suits that environment.

The useful tool for impromptu conference calls, the Plantronics Calisto 620 is a portable wireless UC speakerphone that instantly transforms a laptop or smartphone into a high-quality conferencing device. Small and lightweight, the Calisto 620 provides professional-sounding audio and wireless connectivity. 

Plantronics’ Voyager Legend UC headset system, aimed at mobile professionals, offers connectivity to PC, smartphone, or tablet, and has sensors, precisely-tuned audio, voice controls and advanced charging accessories. 

The Blackwire 700 Series is a versatile UC headset that offers high-quality PC audio and seamless Bluetooth connectivity to mobile phones and tablets. Smart Sensor technology automatically answers a call when you put on the headset, and there’s a detachable cable for taking mobile calls throughout the office.



Polycom offers a full line of purpose-built solutions optimized for Microsoft Lync as well as Polycom standards-based, interoperable voice, video and video content management solutions for Lync. These 40 solutions paired with Microsoft Lync deliver a complete and interoperable end-to-end unified communications solution for voice, video, conferencing and collaboration and connect people from any device, and from any location. Polycom is also a Lync Room System Partner.

Polycom business media phones and conference phones for Microsoft Lync are integral voice components to consider for any Microsoft UC strategy. Built to be an extension of Lync, the Polycom CX series takes the simplicity, ease of use, and familiar Lync interface to environments throughout the enterprise. Combining Polycom HD Voice technology with the advanced presence-enabled telephony capabilities of Lync, these phones and speakerphones deliver new levels of productivity and information to desktops, conference rooms, lobbies, and common areas. The Polycom CX Series of phones are optimized for Microsoft Lync and have full support to Lync PBX functionalities, access to calendar and contacts, rich conferencing, extended functionalities when connected to the PC, and integrated security and manageability.

The Polycom VVX series is a family of Business Media Phones qualified for Microsoft Lync that give busy professionals a high-quality audio and video communications experience. 



Sangoma’s session border controllers are Lync 2013 certified. SBCs act like glue, notes Sangoma, doing LDAP integration, supporting legacy PBXs, and generally enabling all the parts and traffic to work together.

The company also offers the Lync Express appliance, which represents Sangoma’s push into network virtualization. It’s essentially Lync in a box and includes a front-end server, mediation server, active directory server, active proxy, TDM gateway, and SBC.

Sangoma's NetBorder Lync Express integrates the hardware and software elements necessary for a complete deployment of Microsoft Lync, Lync Enterprise Voice, or a wide range of other use cases, including Continuous Branch Exchange, Office 365 telephony support, and legacy PBX integration. Lync Express can serve up to 1,000 Lync seats per unit, incorporate a full-featured SBC for deployments using SIP trunks, can be configured with a variety of PSTN interfaces using the built-in VoIP gateway or with both an SBC and VoIP gateway in the same unit, all of which is fully Lync 2013 certified. The versatile Lync Express appliance can be configured with a variety of PSTN interface types and a VoIP gateway as an IP only device with an integrated SBC, or with both gateway and SBC capabilities in the same unit. Lync Express can cut Microsoft Lync deployment times in half.

SMART Technologies


The SMART Room System for Microsoft Lync has been qualified by Microsoft as fully interoperable with Microsoft Lync Server 2013 and is now shipping worldwide. SMART Technologies says it is one of the first companies to globally ship an integrated hardware and software solution that supports Microsoft Lync in the meeting room.

The conferencing solution, available in three sizes, simplifies the collaboration experience for both virtual and face-to-face meeting participants and provides a seamless online experience through sharing of real-time video, voice and data. Businesses that have started using SMART Room System have benefited from its ease-of-use and found it led to better engagement, enhanced communication and increased productivity.

snom technology inc.


Snom has been a Microsoft UC partner for five years. Today, a total of six snom phones are qualified for Microsoft Lync Server 2013. That includes the 300, 370, 710, 720 and 760, 821 models. Storella points out there’s a difference between Lync optimized and Lync qualified. Optimized, he says, means the solution only does Lync, while qualified means it can support Lync and work with other VoIP systems and identities. For example, he explains, a Lync-qualified phone could be Avaya connected, and at the same time could work with Lync.

The company offers the snom UC Edition firmware (snom Unified Communications Edition), an optional software module for the snom 300, snom 370, snom 821 and snom 7xx series phones, enabling them to connect directly and natively to Microsoft Lync.

It combines the advantages of open standards-based IP telephony by using the SIP protocol to seamlessly integrate with Microsoft Lync and any other SIP-based IP PBX in parallel.

Storella adds that snom continues to develop more capabilities for these devices. One example is a feature called Boss/Admin, which is a shared line. It lets administrators answer the phone for multiple bosses, so involves sharing identities on multiple phones. Presence is also a feature snom offers on its phones. Snom UC Edition qualified for Lync also includes easy sign in with an extension and PIN (so it’s plug and play), SBA support (snom also offers failover identity, so if one identity is cut off users can fail over to a local IP PBX), park orbit support, and picture display (users can assign context, music on hold, and language support so a different language appears on the phone display). The snom phones now also have Lync-Skype federation and two-year warranties. The company also has been in beta with Better Together, which it expects to make generally available this quarter.

Sonus Networks (News - Alert)


All of the session border controllers sold by Sonus Networks are Lync qualified. The company in November announced that the Sonus SBC 5210 and Sonus SBC 5110 session border controllers have achieved Microsoft Lync 2013 qualification for SBC deployments. The Sonus SBC 1000 and SBC 2000 Session Border Controllers also received Microsoft Lync 2013 qualification in several categories, including SBC, survivable branch appliance, E-911 ELIN gateway and enhanced gateway. The SBC 1000 and SBC 2000 also received Microsoft Office 365 Exchange Unified Messaging qualification.

In announcing this news, David Tipping, vice president and general manager for the SBC business at Sonus, commented: “Sonus is the only vendor offering enterprises and service providers a complete end-to-end Lync qualified SBC solution. From the enterprise headquarters to branch offices, Sonus SBCs empower customers to communicate in the most efficient ways – whenever and wherever – with seamless, secure access to unified communications applications such as instant messaging, collaboration, video, conferencing and voice.”
Tipping tells INTERNET TELEPHONY that 25 percent of Sonus product goes through Lync channels and that around 35 to 40 percent of end users served by Sonus infrastructure are users of Lync.

Spectralink Corp.


Spectralink says it is the first company to offer enterprise wireless communication solutions qualified for Microsoft Lync 2013. The Lync qualification applies to the DECT product line as well as the 84-Series Wi-Fi handsets.

The Spectralink DECT and Wi-Fi handsets that have been qualified on Lync 2013 directly interoperate with Microsoft Lync, eliminating the need for a gateway between the technologies. Direct integration reduces both the complexity of implementation and the associated cost of hardware and support services. Using Spectralink’s purpose-built wireless devices, businesses can combine Microsoft Lync with applications and tools customized for specialized working environments such as health care, manufacturing and retail.



Rotterdam, Netherlands-based WORKSTREAMPEOPL created its Anywhere365 solution because it believed the contact center needed to be reimagined. Your business does not need a contact center, according to the company, your business is a contact center, with a variety of individuals with different skill sets. That said, WORKSTREAMPEOPL leveraged Microsoft Lync Server as the enterprise communications platform to natively build its Dialogue Management platform within Lync.

The Anywhere365 Unified Contact Center, the company’s flagship product, is part of its flexible dialogue management system, for which all (IP) voice, chat and web chat, video, e-mail and conference communications can be efficiently and adaptively routed, traced and tracked. Lync Reception Attendant is provided on top of the Anywhere365 UCC platform.

With Anywhere365 as the dialogue management system, powerful business intelligence capabilities have been implemented to allow the organization to extract key information based on business specific dialogue patterns. This helps to better manage workforce capacity, determine bottlenecks and allows for pro-active decisions based on anticipated dialogue volumes and characteristics

Edited by Stefania Viscusi