IP telephony. This approach offers dramatic improvements in gateway performance, sound quality, and overall scalability of the service. By off-loading the dirty work of sampling, compressing, and transmitting audio from the host CPU, these cards reduce latency, improve audio quality, and allow a single server to handle more simultaneous conversations. Several vendors have created DSP cards specifically designed for IP telephony: Dialogic - They are working on a next generation telephony card (known as DM3 IP Link) that is optimized for IP telephony applications. Third party software from vendors such as VocalTec will be required to implement a complete solution. Micom - They have a whole suite of analog, T1 and E1 cards designed specifically for IP telephony. They provide a turnkey solution that completely offloads processing work from the host CPU. Their solution works on DOS, Netware, and Windows NT platforms. Micom provides the software, so no third party products are required. Natural Microsystems - They have developed a card called Fusion that is engineered specifically for IP telephony. This card is typically used by developers to create customized network telephony applications. It has also been incorporated into IP telephony gateways as an OEM product by vendors such as Inter-Tel. For customers desiring a PC based IP telephony gateway, this is definitely superior to solutions where real-time processing is done on the host CPU. These systems will typically offer better sound quality (with fewer dropouts and less latency), more reliable operation (since the application is less OS dependent), and more scalable. Some of these solutions, in particular Micom, also come in at a lower per port price point (US $500 to US $1000 per port). Stand-Alone Ne...
