Sending and receiving texts typically requires a connection to a cellular network, enabling parties at all ends to send and receive packets of information via SMS (Short Messaging Service). However, not a lot of people know that it has been available since before smartphones existed, and it’s possible to easily text over Wi-Fi.
Apple’s iPhones currently have Wi-Fi messaging between iPhones built in, known as iMessage. To send text messages over Wi-Fi using Android or other non-iPhones requires a third-party app, and there are many to choose from.
At the end of 2010, SMS was the most widely used data transmission format. However, as the availability and desirability of non-cellular, Wi-Fi network connections continue to increase, so in turn do our demands for our communication methods to utilize those networks. In contrast with IP (internet protocol) networks, cellular networks are also notoriously insecure and SMS messages are relatively easy to intercept, making Wi-Fi favorable.
The Difference Between Sending Messages Through SMS and Wi-Fi
There’s a bit of confusion surrounding the differences between sending SMS messages and messages via a Wi-Fi network. For example, your phone could be connected to an internet network, but it doesn’t mean you’re sending SMS messages. You could send a Wi-Fi message with your iPhone 12 (like this one from Amazon), to an Android user, but your iPhone will turn it into an SMS because of a lack of compatibility between the two.
With cellular networks being so widely available, most developers utilized, by default, the tried-and-true SMS network when texts are involved. By definition, a subscription to a cellular provider was essential, in one form or another, to be able to use a cell phone at all. And the growing demands for data transmission took advantage of the quickly evolving cellular technology.
With the current and growing availability of IP networks, we’ve got another, more secure option. Many popular apps that include internal texting features can take advantage of IP, and therefore Wi-Fi, networks. Snapchat, Instagram, and Twitter are good examples of apps that include the ability to send and receive texts within themselves and do so via an IP network connection.
But the reliability of cellular network connections, and therefore SMS texting remains, and is still a default feature on nearly all smartphones. As a result, if you haven’t deliberately downloaded an app or adjusted a setting to enable text over IP and you’re using an app that came stock with your phone, you’re probably using SMS.
Why Apple’s iMessage Is Different From SMS
However, if you’re connected to a Wi-Fi network using an iPhone, and texting with another iPhone user, by default your messages are traveling over that IP network via Apple’s iMessage, which is baked into the default Apple messaging app. It’s an app that comes stock with any iOS greater than 8, and it works seamlessly with traditional SMS texting. You’ll know your messages are being sent over IP when they’re blue, and they’re green when it’s an SMS.
Apple iMessage comes stock with Mac OS X devices, as well, easily enabling IP communication between mobile and their slightly-less-mobile devices like Macbooks and iMacs. Since so many apps that Apple offers are used by both iOS and OS X devices, and information is regularly synchronized between the two platforms, it’s clear that iMessage and texting over IP evolved in parallel with this relationship.
However, if you’re using an iPhone like the Pro Max 11 (on Amazon), or a Mac laptop and you’re keen to utilize texting over an IP network with a non-iPhone or Mac user, iMessage will not directly use the Wi-Fi network. In fact, any text messages sent from a device without access to a cellular network, like a Mac laptop, will be sent first via Wi-Fi to the smartphone associated with the text account, and then transmitted as an SMS message.
If you’re keen to use a different app to text over IP – just like the options available for Android users – many apps such as Skype, Whatsapp, and Facebook messenger are also available for iOS. Each of these apps will send and receive texts over an IP network if that’s what the phone is connected to at that time. And they can use cellular if Wi-Fi isn’t available.
Another newish app called Digitone for iOS devices generates a new phone number for your device that works with both calling and texting over IP, for about $10/year for a US phone number, and $5 for a UK number.
Privacy and Encryption of Wi-Fi Texting Options
The IP equivalent to SMS networks are referred to as OTT, which stands for Over The Top. OTT applications by definition use internet networks to send and receive information, and feature encryption as part of their default protocol. By contrast, SMS offers no end-to-end encryption, and as a result, makes texts sent via SMS relatively easy to intercept.
There are many OTT apps available for Android, iOS, and other operating systems. A popular example, WeChat is an OTT app that uses both extensible Messaging and Presence Protocol (XMPP) and SSL/TSL encryption and is regarded as a very secure texting app. WhatsApp, iMessage, and Facebook Messenger are also examples of familiar OTT apps.
Rich Communication Services (RCS): Upcoming Texting Format
As cellular networks globally are considerably more available than IP networks, carriers of cellular phone networks have responded to the security concerns by creating Rich Communication Services, or RCS. RCS was fully adopted in 2016, and while it doesn’t offer end-to-end encryption, it does offer improved security features, equivalent to the standard security protocols of Transport Layer Security (TLS) and IPsec, standard with IP networks.
RCS utilizes the data portion of cellular networks, and if you’re using Sprint, US Cellular, or Google Fi, with a supporting device, you’re already capable of using the RCS network. It does, however, require RCS-capable users at both ends of the text message to work. RCS continues to be included as an option for many devices and cellular carriers, and is set to become the new standard.