Choosing a VoIP Service Provider for Mac CTI
As the developer of Phone Amego, I've had the opportunity to use several providers with different equipment so I'd like to share some of that experience. Depending on what's most important to you, you may need to shop around a little. My priorities are:

(1) Reliability, call quality, ease of use, and helpful support.
(2) Easy to try without a long term commitment.
(3) Support for standard IP phones and adaptors.
(4) Does not lock phones in a way that prevents using CTI.
(5) Flexibility to support forward looking features like HD voice and internet only calls.
(6) Reasonable rate plans based on features I'll use. I don't need unlimited calling to 50 countries, but I'm happy to pay a little more for much better service.

It's worth mentioning that most successful VoIP service providers fall into one of two categories based on their business model:

(1) Full service providers focussed on simplifying the VoIP experience (for business or home use). These providers offer a choice of standard equipment with prices starting around $15 per month (before taxes), or $20-30/mo for unlimited nationwide long distance (on a single line). The best are fanatical about great customer service.

(2) Low cost providers that allow you to Bring Your Own Device (BYOD) and Pay As You Go (PAYG). The best offer reliable high quality calls, good information, and responsive support by Email. Prices start around 1.5 to 2 cents per minute before taxes ($5/month for 911 service and mandated fees).

There are many providers, but some have not put as much thought into their business model to deliver consistent high quality calls and customer service. Finally, choosing a provider with servers closer to your part of the world may be helpful (depending on the network behind the server) to reduce latency. Some providers like CallCentric run their own high performance network so are able to assure excellent connectivity to many parts of the world.

CallCentric
http://www.callcentric.com/?aid=110008

If you just want an endpoint for calls rather than a phone system, one of my favorites is CallCentric. Here's why:

CallCentric is a major ISP co-located with a major telephone facility. This combination of internet bandwidth, low cost, and peering agreements makes for exceptionally robust and affordable service. Internet-to-Internet calls are free, you only pay for access to the PSTN (Public Switched Telephone Network).

CallCentric supports HD voice, inbound fax service, flexible call treatments, and has good documentation. Support is responsive but limited to a trouble ticket system and Email. You can create as many accounts as you need (one per SIP phone) and begin using the service right away at no charge for calls between CallCentric subscribers or other services that support SIP URIs (Internet phone numbers). Calls through the PSTN must be funded, but the rates are reasonable. You can read more reviews here.

Cool:
- HD voice is standard.
- Calls to other CallCentric numbers are free.
- SIP-URI calls are free (Polycom or Yealink phone try this sip:wbdemo@conf.zipdx.com)
- Full 911 service.

My reservations with CallCentric are:
- They don't provide built-in support for call transfers;
- To use 7-digit dialing, you'll need to configure this on your phone or adaptor.

CallCentric is easy to try, and just as easy to cancel if it doesn't work well for you. If you would like to try CallCentric and use the link above, I get a small "agent" credit (thank you). [East coast]

Voip.ms
http://www.voip.ms

Another provider I like is Voip.ms. They offer some of the best wholesale pricing (1.25 cents per minute) and flexible sub-accounts which make it easy to setup multiple phones. Each phone can have its own internal extension while appearing as a single line to the outside. This scheme makes transferring calls and sharing voice mail easy. They also offer explicit caller ID name support (0.8 cents per lookup) with good results. Their web portal is well designed and loaded with examples that explain how to configure most IP phones and adaptors. Another strength is they have servers in several locations covering the USA and Canada along with one in London for European customers.

Cool:
- Easy multiline phone system (great for kids who are frequently on the phone).
- Calls to Voip.ms phone numbers are free.
- Low cost (Canadian telecom taxes are lower than US).

My reservations with voip.ms are:
- No HD voice at this time.
- To use 7-digit dialing, you'll need to configure this on your phone or adaptor (but they provide some examples).
- To get started, you'll need to deposit $25.

Phone.com
http://www.kqzyfj.com/click-5705222-10686247

One of my preferred phone system providers is Phone.com . The company specializes in offering PBX features (virtual extensions, transfers, call groups, conferencing, voice mail, recording, etc...) to small businesses and even home users. The Phone.com website is remarkable for making advanced features easy to understand and configure. You can literally build your own phone system without buying a PBX or hiring an expert. Phone.com offers full provisioning for Polycom and Cisco phones. Support for Aastra phones is currently in beta test. They allow other SIP devices and soft-phones on a self support basis and I was able to use my Yealink phone without difficulty. To use a Polycom phone after signing up, you would set the server type to "HTTPS" and set the server to be: polycom.prov.phone.com . Then just restart your phone and they take care of rest. They don't lock your phone so you can still configure it for CTI. They offer 24x7 US based customer support. When I contacted them about using a Yealink phone, they understood what I wanted and were very helpful. Getting this kind of customer care suggests they really understand their business. There are plenty of companies that cater to corporate clients, but few who really understand home office or micro business users.

My only reservation with Phone.com is price if you don't need a full business phone system
(the first month is free for new customers).

If you want to try Phone.com and use the link above to signup, I get a small agent credit (thank you). This is the kind of office phone system you might have dreamed of at consumer friendly prices (similar to Vonage). Great for a home office or remote telecommuters. [East coast]

Mac CTI
Most IP phones have CTI features built-in, but you will need an administrator password to configure them. If your service provider locks you out of your phone, that's a problem. The providers above all work well with CTI. With other providers, you may want to inquire first.

To use any of these services, you must already have high speed Internet and be prepared to buy and configure one or more SIP phones as needed. This is not difficult to do, but involves plugging the phone into your Ethernet LAN, pressing a menu key to find the IP address, connecting to the phone with your web browser, and entering a few parameters from your VoIP service provider.

Call Quality
Both Phone.com and CallCentric are fully onboard with HD voice and offer outstanding call quality. Phone.com offers a tool to evaluate your network for VoIP. It helps if your Internet router supports QoS (Quality of Service) to prioritize real time audio and video traffic. I've had no trouble using Apple's AirPort Extreme as my primary Internet router. Even though the AirPort Extreme has no user configurable QoS controls, it handles audio and video traffic while simultaneously downloading just fine.

If you do encounter QoS issues, consider getting a second Internet connection to separate voice and data.

In my testing, calls on Voip.ms sounded as good or better than Vonage, but you won't get the surprising range you hear with HD voice.

Vonage
I wanted to mention Vonage because they do a good job of making VoIP simple for consumers. They mostly support their own VoIP adaptors which are pre-configured and easy to use. The call quality is generally good, but your mileage may vary (YMMV). One of our phones worked great, while the other had occasional issues. Compared to a traditional phone or cable company, the cost is about half for basic service, and far less for international calls. The disadvantage with Vonage is they don't support business IP phones with advanced features and CTI (beyond their own limited click-to-dial service). [West coast]

Vonage Companion for Mac is available here.

Q: What about hosting your own PBX?
A: For smaller businesses, hosting a commercial PBX requires a larger upfront investment, ongoing technical support, and limits flexibility to add or relocate extensions anywhere at anytime. Voice over IP has clearly won for low cost, features, and flexibility. The trend is to skip the PBX, strengthen your Internet connection, and go with a hosted provider. A few years ago, VoIP had a reputation for poor audio and unreliable service, but these problems have largely been solved as long as you have good Internet connectivity and a solid provider. VoIP has matured into an enterprise solution that businesses use every day.

Depending on your application, hosting your own PBX may still be attractive. The open source PBX system Asterisk is best suited for professionals or dedicated hobbyists in my opinion. PIAF (PBX In A Flash) provides a basic Asterisk installation you can get up and running in 30 minutes and encourages you to learn from there. pbxnsip has become Snom One Free. Kerio Operator adds a much friendlier web interface to Asterisk and packages it as a commercial product.

I’ve heard some good things about the following:


One feature I like about these is how they work with popular SIP phones.

Q: Any recommendations for hosting Conference Calls?
A: I've had good experience with FreeConferencePro.com . The service is free and supports itself by collecting a small call termination fee from the respective phone companies for each minute used.

Other Resources:
Understanding VOIP