When evaluating Internet telephony products as an alternative to your existing telephone system, ask yourself these five questions:
1. Can a system provide additional dial tone over your existing lines? For example, suppose you have 48 public switched telephone network phones, with at least 12 of the PSTN lines being used for intracompany communications. If you were able to move six channels to your frame relay net or the Internet, that would free up six lines and perhaps obviate the need to install another T-1 line.
2. Can your PBX interoperate with the system without modification? The last thing you need is to create more problems for your telephone system than you solve. PBX systems are still 99.99% closed architecture, so there's no way a PBX can or should be modified or extended to support a gateway. The PBX or telephone system should see no difference between the digital or analog phone jacks coming out of the gateway you buy and the feed coming from the central office or tie line.
3. Can the system support computer telephony services (such as voice mail, interactive voice response and fax-back) without add-ons or modifications to either side, such as digit repeating or amplification technology? If a corporate user tries to reach a voice messaging server in a remote location, will the route over the IP network support interactive technologies that use in-band dual-tone multifrequency signaling?
4. Does the technology save you money, and can you show your return on investment? Routing calls over the Internet, or a corporate intranet, does save money. Someday, however, calls over the Internet may be taxed or subject to tariffs.
5. Can you use the technology to soak up an oversupply of private bandwidth? In other words, if you maintain a wide-area data network that is loaded doing data interchange during the night, can you use it for voice communications during the day? Companies with multiple locations linked together via a WAN can benefit greatly from the ability to place voice calls over a frame relay IP network that has available bandwidth during business hours.
RELATED LINKS
Back to Issues and Trends
What to consider before getting into VoIP, plus hyperlinks to additional resources.
Interactive buyer's guide
Find a gateway based on your specific criteria, or download a spreadsheet containing specs for 26 of them.
Shapiro is president and CEO of TekMatix, Inc., a systems integrator in Coconut Creek, Fla. He is the author of Computer Telephony Strategies, among other titles. He can be reached at jeffreys@ tekmatix.com.
