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Comparing VoIP service offerings

A laundry list of the features to look for when comparing VoIP providers.

Today, the number of telephone companies and service providers offering IP-based phone service continues to grow (there are at least a dozen vendors in this space, and numbers appear to be growing rapidly). With so many VoIP calling plans on the market, it's helpful to have a good list of the features you should look for to compare costs and evaluate individual offerings. This got me to thinking about what one should look for when shopping around for VoIP service, which I present in the form of an alphabetized laundry list:

  • Adapter cost: charges to the customer for the adapter that permits a standard POTS handset to be hooked up to a (broadband) Internet connection. This is free in most cases, but some vendors charge for adapters when customers opt for unlimited calling plans.
  • Block international calls: Can be invoked to disable international calling capabilities, helps avoid unwanted charges and defeats most dialer (malware) programs. Nearly all services support this feature.
  • Call hunting: when customers have more than one number from the same service provider, a call rings all such numbers in a specified order. All services I could investigate support this feature.
  • Do-not-disturb: This feature permits customers to divert all incoming calls to voicemail with or without a "customer is busy right now" message. Nearly all services support this feature.
  • Enhanced directory (411) services: combines the best of computer search engines with voice based services; available from most service providers.
  • Fax services: most service providers offer plans where customers can pay a modest additional fee, or purchase special "business plans" that bundle a fax line in with other voice services as part of a single VoIP account.
  • Fees (monthly): usually comes in basic and unlimited calling plans. Basic puts a ceiling on the number of minutes covered and imposes a per-minute rate for calls over the limit; unlimited calling costs more, but imposes no ceiling (or extra charges) regardless of usage.
  • Free in-network calls: means that calls to other users on the same VoIP network don't count toward minute totals for basic plan customers. Typical from most providers for all plans, but may apply only to unlimited calling plans from some providers.
  • Inbound 800 number: lets customers pick up inbound call charges by providing outside callers with a toll-free number; available only in a minority of plans.
  • Number of area codes accessible: A strong point of comparison, this item offered some of the widest variation from plan to plan (lowest number: 127; highest number: 179; by comparison, there are over 600 defined area codes, over 300 for US and Canada).
  • Number of phone lines supported: 1 or 2 in most service offerings.
  • PC-based virtual phone service: for those on the road traveling with a laptop, plugging in a USB headset turns an Internet-connected laptop into a phone with the necessary software. Allows customers to continue placing and receiving calls irrespective of location. Usually an added-(monthly)-cost option.
  • Teleconferencing: offers the ability to link multiple parties together in a single conference call. Surprisingly, most VoIP services offer support for many more parties than conventional phone service (some max out at 3 or 6 callers, others at 10; some services charge extra for this feature).
  • Virtual number support: lets the customer choose a public phone number in another area code, and maps that number to the underlying SIP address. Supported in most plans for a modest additional monthly fee.
  • Voicemail services: all service providers offer some variation on this complex theme, most include voice or e-mail message delivery, local access to voicemail in all supported area codes, customizable voicemail controls, online user guides and examples, quick setup guides, multiple greeting types, and more. An important point of comparison, especially for those interested in particular voicemail features or functions.

Indeed, there are yet more features and functions that can help potential customers distinguish among VoIP service offerings, but these are the ones my recent experience has convinced me are most noteworthy. Whenever you're shopping for a service, however, careful attention, consideration, and comparison are always highly recommended! (Note: the companies that were surveyed for this story included AT&T, Vonage, VoicePulse, FWD, MyPhoneCompany, Time-Warner Cable, Packet8, Lingo IP Phone Service, Cheap Call, GalaxyVoice, LATIC Communications, and, among many others. Yahoo maintains a pretty complete list of Internet Telephony Service Providers.)

Ed Tittel is a regular contributor to numerous TechTarget Web sites, and the author of over 100 books on a wide range of computing subjects from markup languages to information security. He's also a contributing editor for Certification Magazine, and edits Que Publising's Exam Cram 2 series of cert prep books. E-mail Ed at

This was last published in August 2004

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