If I have the phone number of a fellow iPhone user, but no cellular connection, just wifi, will Apple Messages resolve the phone number to the user’s email address?
It goes through Messages to the recipient’s iCloud account, the number is bound to the iCloud account (as is, usually, an email address), it goes through Messages, whether the person is currently online or not, whether the user is on cellular or Wi-Fi. The message will be received as soon as their device attaches to the Internet. It doesn’t get diverted to email, so it won’t land in Mail or Outlook or GMail etc.
If the devices are connected to Wi-Fi, it still goes to Messages on the user’s devices that are online.
Messages/iMessage only uses its own protocol, unless the recipient doesn’t have an iCloud account, in which case, it drops back to SMS (currently) or it will use RCS in the future. But if it is Apple user to Apple user, it goes directly, end to end encrypted from the sender to the recipient, using whichever network connection is currently active.
For example, I have an iPhone, an iPad and a Mac, plus an Apple Watch. Only the iPhone has a cellular radio in it, but they receive the messages directly in Messages.
So, in short, when the recipient has an iCloud account, it goes directly through Messages all the way, whether that account has an attached telephone number or email address to identify it is irrelevant, it is the iCloud account that is key.
This is how most messaging platforms work, like Signal, Telegram, Threema, WhatsApp etc. the messages go to the user’s account on that platform directly, and securely, whether the user has registered with a telephone number or some other “handle”, such as an email address.
Thanks for the explanation. Now I know that cellular is not required to exchange messages within the Apple ecosystem. Makes my life lots easier.
I’m exchanging messages with someone in New Zealand. Do I just address my message to their local phone number? I’m assuming that no country code or regional/area code is required?
1 Like
You need the full international number, including the country code, or their iCloud address.
The phone number system allows phone numbers to be used in multiple places at once, because it is what is technically know as “leftwise unique”. Interestingly, it’s easier to think of this from right to left.
The phone system grew organically, and started as unique systems in parts of different cities. Each user was give a subscriber number. As the parts then got interconnected they needed a way to route a call to different subscribers with the same number but in different areas, so they added a prefix to address the different parts to make them unique. This prefix became known as the exchange.
They also reserved some numbers in the prefix to allow for special dialing, such as to call the operator directly. So a phone number in North America grew to be NXX (for the exchange), which was [2-9][0-9][0-9] followed by XXXX (for the subscriber number) which was [0-9][0-9][0-9][0-9].
Initially the interconnection was handled by a human, so you were speaking the number to connect to (or even a name, and the human operator knew the number) so it was possible to leave off parts to call someone who was close by. For example, you neighbour might have been possible to call just by dialing the 4 digit subscriber number, because the exchange would have been presumed.
As the number of subscribers grew, and as automation replaced humans, they came up with a minimum number of digits to simplify the decoding of the number. The minimum number in North America became 7 digits. To make calls between cities at greater distances, they still relied on humans for a long time. That was because the number of trunk lines between cities was not very high, and a call was relayed through multiple human operators to connect it along the hops in its path (because there was no computer to do the routing, and there was not a direct line between every city’s exchange and every other city’s exchange.) You needed to dial a special code to get the operator involved, and they selected the digit 1 (and later 0 too) for this purpose.
Once automation took over, it could tell you were making a long distance number as soon as you dialed the 1, it didn’t need to wait for more digits, so it would start the routing in to the long distance network, and continue it as you dialed. So in essence the system went through “thinking” like: Oh I see a 1, this is long distance, I can now expect an exchange number, so collect three digits to find out which exchange. Oh I got the correct exchange, now it needs to collect a subscriber number to complete the call.
Basically, it’s peeling of parts from the left, which is why they need to remain unique so it can continue to correctly identify them as their dialed.
Because of this, you can tell the difference between the types of numbers like:
NXX-XXXX (rarely possible to dial any more, especially because exchanges and area codes can be duplicated)
1-NXX-XXXX (calling someone in another city, the 1 was used to indicate where long distance charges [used to] apply, this is almost impossible to call now, because they needed more exchanges and area codes and they became impossible to tell apart)
NXX-NXX-XXXX (the area code is part of the number in many large cities now, originally you could tell an area code by the fact that it’s middle digit was 0 or 1, but that is no longer the case.)
1-NXX-NXX-XXXX (calling someone in another area code (city), the 1 was used to indicate where long distance charges [used to] apply)
011-CCC-NXX-NXX-XXXX (011 is the international dialing prefix, CCC is a country code, which has 1, 2, 3 or more digits, usually longer the smaller the country/population, and what a phone number looks like inside of different countries varies and is not the same as North America)
Country codes are also leftwise unique in and of themselves. The first digit identifies the type of number or the area:
1 - United States, Canada, Caribbean
2 - Africa
3,4 - Europe
5 - Central & South America
6 - Oceana & South Pacific
7 - Russia & vicinity
8 - East Asia
9 - West & South Asia, Middle East