Time Capsule & iPhone Hotspot & Airport Express

Follow up. I was able to test using a current version of the AirPort Express. It is a classic good news - bad news situation.

The good news......a current A1392 version of the AirPort Express can be configured to "join" the WiFi signal provided by an iPhone hotspot.....and the Ethernet port on the AirPort Express is enabled, so a computer (or a Time Capsule) could be connected to the AirPort Express using an Ethernet signal and "bridge" to the iPhone hotspot.

The bad news.....the WiFi connection and Ethernet connection to a Time Capsule will only be as fast as the hotspot allows....which might be in the 1-10 Mbps range depending on your service and connection quality. So, Internet connection speeds are going to be quite slow.

Your mileage may vary, but if you also configure the Time Capsule to provide its own wireless network, you will be able to back up your Mac(s) using that wireless network at reasonably good speeds.....since backups do not occur over the Internet connection, only over the "local" WiFi connection.

Mac(s)....could also back up to the Time Capsule using an Ethernet connection.....assuming that the Mac has an Ethernet port. Otherwise, you will need to use a Thunderbolt to Ethernet adapter for this type of connection.

As I need to connect the Time Capsule by Ethernet to something, I understood this needed to be an Apple product (airport express) as opposed to a 3rd party router ?

Apple wireless routers allow the TC to connect by wireless.. except in this instance.. due to the bridge from wireless to ethernet.

It is simply the limitation that Apple build into their products so they cannot be used as universal repeater or bridge (except for the express can do bridge).

Using a more generic router is fine because wireless to ethernet bridge is pretty much transparent conversion of packets.. no routing is happening so any brand can work ok.

I did dig around some more and there are certainly 4G routers made which will tether to iPhone.. D-Link was one brand that seems to support it.. but unfortunately the support comes and goes as Apple changes the iOS.. so it can be a case where you need to find out exactly which model phones and iOS versions are supported. My guess is that iphone X being the most recent model on the most recent version iOS may be more problematic.

The tether to computer should always work because of iTunes install on either windows or Mac. The drivers are built into iTunes..

The Time Capsule does not need an Internet connection to create it's own "local" wireless network. But, the advantage of connecting the Time Capsule via the AirPort Express would be that Macs could always remain on the Time Capsule wireless network for both their Internet connection and Time Machine backups. So, backups would always occur automatically this way. Set and forget.

If the Time Capsule did not connect via the AirPort Express, then you would have to manually switch Macs to the 4G network when you wanted them to connect to the Internet and then manually switch back again to the Time Capsule network when you wanted to back up. Then manually switch back to the 4G network again after the backup was completed. Too much of a hassle for most users.

On the other hand, if you only plan to back up each Mac once a week or so, then manually switching WiFi networks might not be too much of a hassle. This would be the more complicated way to do things though, with more chances for things to go wrong. And, because you would be backing up a weeks worth of data this way, the backup will take much longer than frequent automatic backups that run all the time in the background.

Can I get old Airport Express units to access iPhone mobile hotspot and then be connected to the Time Capsule by cable and thus allow Time machine to work as normal.

Sorry, but no.

With a new AirPort Express.....possibly. But, I don't have one handy to test at this time. Perhaps another user can check on this and report.

There are solutions like running the phone tethered to a router .. I can try to find a router that works with iPhone combo.. but that would be a better setup than using the phone as hot spot. However I am finding it hard to find a suitable combo.. you can use Android phone.. because it uses standard linux.. but iOS will probably need special drivers which the routers won't have available.. so most people do revert to the hotspot solution with iphone.

But you can tether to a computer if that would be a reasonable setup and use ICS. Again not something I would use for normal every day use.. but if you want internet on your computer.. which is the main device connected at all times.. it can be relative simple setup.. and wired connection to the phone will keep it charged at the same time.

Or there are plenty of other brands of wireless bridge (many low end TP-Link wireless routers for example have wireless client or wireless bridge mode built in).

In the end though I do think if the 4G service becomes your standard internet connection.. and you grow tired of swapping your iphone to hotspot mode (or someone else needs the internet while you are away) buying a proper 4G wireless router is going to end up well worth it.

I can probably be any product that is capable of connecting to a 4G network and then provides an Ethernet Internet connection to the Time Capsule.

We suggested a current model AirPort Express because we tested using that product, and your original question asked about using an AirPort Express as a "bridge" to your 4G wireless network.

LaPastenague suggested buying a 4G router (with an Ethernet port), which would work as well.

You would want to take advantage of the Time Capsule's ability to create a wireless network because that will be a much faster network compared to 4G. So backups using the Time Capsule WiFi would be 4-8 times or more faster than using the 4G wireless.