VoIP or Voice Over IP, the latest in wireless communication works take a call, changing from analog to digital signals and send these signals over IP network or broadband and finally terminate it on the PSTN. Call charges are greatly reduced using this technology. The advantage is that software emulation phone can be loaded on a laptop so enable you to access the service even while traveling.
VoIP SIP uses Session Initiation Protocol (), a peer-to-peer technology that allows computers to communicate with each other without having calls routed through some center. For calls from one SIP enabled phone to another cuts call charges drastically.
The Asterisk System comes with the Asterisk server that controls things like teleconferencing, voice mail, queues and keep music. The hard phone is a digital phone that has an Ethernet jack to communicate with the server using SIP protocol. They, including wireless version, are not very expensive. The soft phones are implemented in software and can be attached to a computer. Asterisk runs primarily on Linux, open source operating system.
Cisco has telephony solutions that are network based and run on the way. They are scalable and work well in a multi-user environment in mulitple locations. The UC500 is a suite of bundled services such as routers, switches, security, telephony and wireless functionality in one device. This greatly reduces the costs for companies that are planning this service. The Cisco Call Manager Express uses SIP to connect the phone via the Internet and also has properties UC 500 makes it more viable for medium scale. Additonal features include paging, intercom, ICMP and class limitations of handset users.
Avaya IP Office uses IP technology to carry voice and data communications, messaging and customer management across multiple sites with 2 to 300 people. It allows you to work from anywhere, host conferences, integrate applications, measure and improve customer satisfaction at the touch of a button. It is cost effective as it reduces long distance calls, conference fees, supports remote workers and helps keep business cooperation and up-to-date.
Three products can be compared on the basis of the following several criteria:
• Number of extensions: Asterix can support up to 100 extensions while Cisco and Avaya can go up to 360 extensions so suporting large organizations as well. This improves flexibility and helps to reduce costs in the long run.
• Free software: Asterisk is free and runs on the Linux server. This makes telephony solution cheaper than either Cisco or Avaya that make extensive use of routers and switches to communicate.
• Installation and maintenance: Asterisk programmer’s dream as it is open source and can be changed at will. However, for users, it can be a nightmare. Support and service is better with Cisco and Avaya set names in the industry.
The main thing going for Asterisk is its cost. However, it is not always wise to look at the initial cost items. Other criteria such as flexibility, integration of one device with other already existing, interoperatability and long-term options should be considered while choosing one product over another.