Selsius Systems

Selsius Systems

Company type	Private
Industry	Telecommunications
Founded	July 1997 (1997-07)
Founder	Richard Platt, David Tucker
Defunct	November 1998 (1998-11)
Fate	Acquired by Cisco Systems
Headquarters	Dallas, Texas , United States
Key people	David C. Tucker (CEO), Richard B. Platt (VP Engineering), Kevin Brown (VP Sales and Marketing)
Products	IP PBX platform, IP telephones, Selsius-CallManager software, VoIP gateway devices, voicemail systems, automated attendant interfaces, softphone clients

Selsius Systems was a Dallas, Texas-based telecommunications firm that focused on pioneering Voice over Internet Protocol (VoIP) technologies. Established in 1997 by Richard Platt and David Tucker, the company specialized in creating and distributing IP telephony solutions until its purchase by Cisco Systems in November 1998.

Products

The company’s portfolio included an IP PBX platform complemented by a series of IP telephones, the server-driven call control software known as Selsius-CallManager, VoIP gateway devices, and voice-related applications such as voicemail systems, automated attendant interfaces, and softphone clients.

History

Selsius began operations in July 1997 as a spin-off from Intecom, a Dallas-based PBX manufacturer. Leadership comprised CEO David C. Tucker, VP of Engineering Richard B. Platt, and VP of Sales and Marketing Kevin Brown. Their inaugural product was the Selsius 30SP, recognized as the first commercially released IP phone, with initial sales made to Southwestern Bell’s TRI laboratory.

The origins of Selsius trace back to Incite, a division within Intecom supported by the French conglomerate Lagardere SCA. Incite initially developed a video PBX system featuring distributed call control software but encountered limited market interest. Under Tucker’s guidance, the team restructured into the independent entity Selsius, expanding its workforce from 35 to approximately 55 employees by the time Cisco acquired it. The foundational call control software was subsequently integrated into Cisco’s CallManager and evolved into what is now known as Unified Communications Manager—forming a critical element of Cisco’s unified communications strategy.

Following the acquisition, founders Platt and Tucker continued with Cisco as executives managing IP Telephony products. The majority of original Selsius personnel joined Cisco’s development divisions; some chose buyouts or pursued other opportunities—Kevin Brown became CEO of IPcelerate by 2006. At the point of acquisition, CallManager was still under development to fully mature within Cisco’s product lineup.

Selsius Legacy

Selsius’s impact endures through Cisco Unified Communications Manager and IP phones utilizing the Skinny Client Control Protocol (SCCP), initially created by Selsius engineers for VoIP services. Cisco has since retired analog gateways that operated using the Skinny Gateway Control Protocol (SGCP). Unified Communications Manager acts as the central call processing system within Cisco’s Unified Communications framework and had generated around $1 billion in revenue for Cisco by 2005. Moreover, associated network infrastructure sales—including switches and routers—have been estimated to produce revenue up to three times that figure. In its first year, Selsius sold roughly 3,000 IP phones; by 2006, Cisco was selling an equivalent number—built on Selsius technology—every eight hours.

Learn More About Selsius

Richard Platt contributed the foreword to Cisco CallManager Fundamentals, the first Cisco Press publication on Unified Communications technology authored by original Selsius team members John Alexander, Chris Pearce, Anne Smith, and Delon Whetten. In his introduction, Platt emphasizes Selsius’s pioneering achievement: executing the inaugural telephone call entirely over Internet protocols using a genuine IP phone controlled by an IP-based server named CallManager. This work, now in its second edition, documents a significant milestone in IP telephony development.

Mark Nelson, a Cisco employee, has chronicled Selsius’s history along with profiles of key contributors—Platt, Tucker, Alexander, Sanders, and Hahn—in a blog post reflecting on the company’s engineering heritage following its integration into Cisco. Prior to Cisco’s successful acquisition of Selsius, Nortel Networks had expressed interest but withdrew after failing to secure employee backing.