While the pace of change in network technology continues to increase, global deregulation of telecommunications has allowed more service providers to compete for data, voice, and video network services. Only companies who have designed their network infrastructures with these factors in mind will be able to benefit from the lower prices caused by increased competition and protect themselves from "technology lockout" in the future.The voice over IP feature enables the Cisco 2600 and Cisco 3600 series of modular routers to carry voice traffic, such as telephone calls and faxes, over an IP network simultaneously with data traffic. This two port E/M voice/fax-over-IP interface module, for slide-in in NM-xV of a CISCO261x/36x0 has two RJ11 ports for connection to a telephone system.