Phase 2: Software
NANNA NANNA NANNA NANNA BAT APPS!
Voice Over Internet Protocol (VOIP) can be done entirely with software. Placing calls and text messages over the Internet usually requires a client application to access a service provider. Most service providers also have client applications, and some service providers, such as Skype or Apple will only allow access from their proprietary applications. The list below is organized, from specific purpose to general purpose, and from proprietary provider to applications that work with any provider.
Software Tied to Specific Hardware and Services:
Facetime - iOS, Mac
Video Chat, Voice Chat, IM
Facetime is Apple's proprietary calling and messaging application for the iPhone and iPad. Using it requires an iOS or Mac OS device, and it can only call other Facetime enabled devices. The application is simple to use, and as of iOS6, can make calls over wifi or mobile broadband. Facetime does not allow you to call the PSTN or to send messages via SMS.
OBION App - Android, iOS, Windows
Voice Access to OBI ATA
The OBION app only works with an OBI ATA, which you can learn more about in the Batphone Hardware section.
The app is available for Android, IOS, and a middleware application exists for Windows that lets you use a SIP client to access your OBI ATA.
Remotely accessing your ATA will let you make calls from your OBI ATA as if you had picked up an extension in your home or office. This is different than using your VOIP provider or Google Voice credentials with a soft phone in that the call physically originates from the OBI device. This could provide remote access to a land-line via the app, assuming of course that you have a land-line and an Obi ATA with land-line capability.
Software Tied to a Proprietary Service:
Skype - Android, IOS, Windows, Mac, Linux
Video Chat, Voice Chat, IM, PSTN number (paid), PSTN calls (paid),
The free Skype application only works with the Skype service, but Skype is one of the most popular VOIP applications in the world. It boasts millions of users, integration with a number of Microsoft services and has clients for most popular platforms. Voice, video and instant messaging to other Skype users is free.
Skype also offers paid services for outgoing calls to PSTN numbers known as SkypeOut, for incoming calls via a PSTN number known as SkypeIn, and text messaging to and from mobile numbers. There are monthly fees associated with the SMS and PSTN services, but outbound minutes can be pre-paid as well.
Google Hangouts - Windows, Mac, Linux, iOS, Android
Video Chat, Voice Chat, IM, PSTN calls (free)
Google Hangouts is the free instant messaging, voice and video chat service built into GMail. Hangouts are persistent chats, similar to chat rooms. You can also use Hangouts for voice or video calling. GMail is a very popular email service, and adding contacts to Hangouts is as simple as emailing another GMail user. The handiest feature of Hangouts is that it integrates with Google Voice so that you can receive phone calls on your PC or iOS device.
The iOS verion of Hangouts lets you make and receive Google Voice calls over wifi. Calls to your GV number ring the hangouts app on iOS, much like it works on Windows. Support for GV calling via Hangouts on Android is said to be coming soon, presumably before API access shuts down in May 2014.
Google Voice App - Android, IOS
PSTN Number (free), PSTN calls (free), SMS (free)
There are free Google voice apps for Android and IOS that facilitate using Google Voice on a smart phone or tablet. You can learn more about the Google Voice service in the Batphone Services section of this website. If you run your GV app on a smart phone, it will allow you to make calls from your phone using your GV number instead of your mobile number. You can also forward GV calls to your mobile number. If you run the GV app on a device that isn't a phone, like a tablet or media player, you can make outgoing calls using the Click-to-Call feature that will ring one of the numbers that you have your GV number forwarded to. You cannot use the GV app to make GV calls over WiFi until integration with Google Hangouts is completed (see the Google Hangouts entry above). On both smartphones and tablets, the GV app can send and receive text messages and play voice mail messages, even over WiFi.
Talkatone App - Android, IOS
PSTN Number (free), PSTN calls (free+credits), SMS(free)
The Talkatone (TAT) app is available for free on both Android and IOS and used to let you make and receive Google Voice calls, text messages, and GChat instant messages from your tablet or smart phone. Since Google is shutting down API access to GV in May of 2014, it is rendering the original version of Talkatone basically useless.
In response, TAT has revamped its service offering to be a stand alone messaging and calling app. Like GV, Talkatone is offering a free number, unlimited incoming calls, and unlimited text messaging. Calls to other users of the Talkatone app are free.
Unlike GV, TAT requires credits for outgoing calls to the PSTN. Each credit is equal to a minute of outbound calling, and users can receive 10 free credits per month. Additional credits can be purchased at the rate of 60 credits for 99 cents, or 1.65 cents per minute, which is kind of pricey when compared to VOIP services like VOIP.MS, but not bad when you factor in the unlimited inbound calling. It's also not a bad price when compared to the 2.3 cents per minute for calls to the US via Skype, or 10 or more cents per minute for calling with a prepaid mobile.
Talkatone is still useful with GV, because you can configure your Talkatone number as a mobile phone in GV and have incoming calls and texts (both of which are free and unlimited) forwarded to your Talkatone app. GV does this magic number translation thing, so if you reply to a text that GV forwarded to your mobile, it looks like the text came from your GV number. Since incoming calls are free, you can use the GV Click-to-Call feature on the GV website to make an outgoing call that rings your Talkatone app first.
Using your Talkatone number as a forwarding phone in GV makes it easy to use the Talkatone app to add a second GV line to your smartphone or tablet. You can use the official GV app and call forwarding for your primary number (email@example.com for example), and then use Talkatone as a second GV account (firstname.lastname@example.org for example).
TextNow App - Android, iOS, Windows
SMS (free), PSTN Number (free), PSTN calls (subscription/credits),
TextNow is a free app that gives you a free mobile number that can send and receive free text messages. The app also lets you make and receive calls with a subscription or with earned credits. SMS is free and unlimited, and prepaid voice minutes range in price from 1.5-2 cents each. The per minute rate is not great by VOIP standards, but it is still much better than Skype or a prepaid mobile. TextNow also lets you place calls over wifi or mobile broadband. If you do not use your number on a weekly basis, you will lose it, so be sure to have a plan for keeping the line active.
TN is similar to Google Voice in that it does not offer SIP credentials or a SIP URI, your calling and messaging is basically confined to the TN app. TN differs from GV in that it also runs a prepaid mobile phone service that works over 4g data or wifi. The mobile service requires the purchase of one of their somewhat outdated smartphones and you can get unlimited text, and several hundred voice minutes (and unlimited incoming calls) for a little as $20 per month. TN differs from Talkatone in that TAT offers unlimited incoming calls from the PSTN, and there is no mobile service offered by TAT.
Various Social Networking Chat Apps -
Video Chat, Voice Chat, IM, Picture Messaging, Audio Messaging
Social Networking apps like Facebook Messenger, Viber, or WhatsApp are real time chat applications. These services offer real time, text, voice and video chat, but do not offer connectivity to the PSTN. Many of these services also offer audio and video messaging where you can create a short video or audio file and send it to one or more contacts through the app.
These apps offer many great features and have millions of users. They can be very handy to use especially if your network of friends and family are already using them, so feel free to make use of them. The goal of this site is to provide supplemental or alternative access to SMS and the PSTN, so social networking chat apps are kind of outside the scope of this website.
Some of these apps do offer outbound calls or texts, but I haven't used them enough to know how they work, or to be familiar with their pricing structures.
General Purpose VOIP Software:
CSipSimple - Android
CSipSimple is a softphone for Android that works with generic SIP providers like VOIP.ms. It is handy for adding calling capabilities to a tablet, or to add an additional line to an Android smartphone.
MicroSIP - Windows
MicroSIP is a tiny softphone for Windows. You can configure it to make and receive SIP calls on your PC. You can install it locally like any other program, or you can run it from a USB thumb drive so you don't have to install any software. This is handy if you move from computer to computer that you cannot install software on. When paired with a headset you can turn any Windows PC into a VOIP telephone.
Counterpath Softphones - Windows, Linux, Mac, Android, iOS, other mobile OSes
CounterPath makes a few different softphones for just about any kind of computer, tablet, or smartphone that you can think of. I have used the Bria softphone for the iPad as well as X-Lite client for Windows in the past. Both applications support multiple lines, X-lite supporting two, and Bria 3 supporting up to six. If you are new to VOIP, I recommend using X-Lite on a PC to test things out before buying an ATA or IP phone.