Why You Can Trust CNET T-Mobile Personal CellSpot review: Top performance and features, for free
The Personal CellSpot is an outstanding deal for T-Mobile customers. It has the best Wi-Fi performance, an excellent set of features, great support for Wi-Fi calling, and for the most part, it's free.
Announced as T-Mobile began a big expansion of its Wi-Fi calling feature, the CellSpot is a great deal for T-Mobile users who don't get a cell signal at home. Not only is it free (after a $25 deposit, but with no monthly fees), it's also an excellent Wi-Fi router delivering excellent performance and a great set of features, rivaling the best home routers on the market. But that's to be expected, since it's the rebranded version of the Asus RT-AC68U , which earned CNET's Editors' Choice Award for super-fast performance and top-notch features.
T-Mobile Personal CellSpot
The Good
The Bad
The Bottom Line
And as a cell signal supporting device, the CellSpot (aka the TM-AC1900) worked very well with handsets that support Wi-Fi calling. I was able to make calls via the CellSpot's Wi-Fi signal, even in places where there was no regular cell signal at all, with great call quality.
All things considered, for T-Mobile customers, the CellSpot is an outstanding deal with no catches. MetroPCS customers will have to buy it for $99, but even they should pick one up today. For other great, though not free, choices that also support Wi-Fi calling well, check out this list of the top 802.11ac routers on the market.
Design and setup
The T-Mobile TM-AC1900 is first and foremost a standard Wi-Fi router. As such, any Wi-Fi-enabled device, from a laptop to a phone, can connect to it to transmit data. And of course, it also lets Wi-Fi calling-enabled smartphones, such as the Samsung Galaxy S5 or the new iPhone 6 and 6 Plus , make regular calls.
As I mentioned, the CellSpot is basically the same as the Asus RT-AC68U. That gives it support for the three-stream setup of the 802.11ac Wi-Fi standard with a top speed of up to 1,300Mbps on the 5GHz band and up to 600Mbps on the 2.4GHz band. (Read more about Wi-Fi standards here.)
On the back the CellSpot has four Gigabit LAN ports (for wired clients), one Gigabit WAN port (to connect to an Internet source, such as a broadband modem), one USB 3.0 port, and one USB 2.0 port. You can use these USB ports to host printers, external storage devices, and even a cellular modem. Other than the T-Mobile branding on the front, it looks exactly the same as the RT-AC68U.
It's very easy to set up the CellSpot. Out of the box, it comes with two preconfigured Wi-Fi networks (one for each band) with the setup information printed on its back. All you have to do is turn in on, connect its WAN port to the broadband modem, and you're ready to go.
(Note that the CellSpot works best for Wi-Fi calling when it connects directly to the broadband modem, and not via another router. However, Wi-Fi calling works as long as the router is connected to the Internet.)
To customize its settings, you'll need to use its Web interface. To do this, from a connected computer, just point the browser to the router's default IP address of 192.168.29.1 and log in with "admin"and "password" as the username and password.
Excellent feature set, Wi-Fi calling supported
Once logged in you'll notice the CellSpot has the same interface as the RT-AC68U. However, it has a slightly different feature set.
The CellSpot retains most of the RT-AC68U's features, including support for all common home network settings, a built-in VPN server, robust QoS features, a helpful visual network map, support for IPv6, and many other things commonly found in high-end routers. (For more on these features, check out the review of the RT-AC68U .)
There are a few differences, however.
First, the CellSpot supports only four guest Wi-Fi networks (two on each band), whereas the RT-AC68U supports six guest networks. Secondly, the CellSpot doesn't offer Dual-WAN (the RT-AC68U does), a feature that turns one of the four LAN ports into a second WAN port so that the router can work with two Internet providers (such as cable and DSL) at the same time. This is not a big deal, however, since most of us don't need more than two guest networks or more than one LAN port.
And finally, the CellSpot has something the RT-AC68U doesn't have. It includes T-Mobile's Evolved Packet Data Gateway (ePDG) technology, and hence supposedly offers better support for Wi-Fi calling. In my testing it seemed the CellSpot automatically prioritizes its Internet bandwidth for cell-related services no matter how you customize the router. Normally, you need to configure the router's built-in QoS feature for Internet prioritizing; the CellSpot takes care of this for you.
Technically, Wi-Fi calling depends on just the carrier and the smartphone. This means a Wi-Fi-calling-enabled smartphone can place and receive voice calls or send and receive text messages using any Internet-ready Wi-Fi network. However, T-Mobile says the CellSport comes with patent-pending technology that prioritizes voice calls over other Wi-Fi traffic. This means with the CellSpot, you can make qualitative voice calls even when the router is busy performing other tasks, such as media streaming or heavy file downloading.
Wi-Fi calling brings cell coverage to a whole new level. This is because, to connected smartphones, the Wi-Fi signal coverage is now also the cell coverage. And since it's much easier to bring an Internet connection to places where cell signals can't reach, such as the lower levels of a building or the basement of a home, the CellSpot allows not just wider but also deeper cell signal penetration. It's also significant that this coverage also extends to outside of the US. Using Wi-Fi calling, you can use your T-Mobile phone overseas, without roaming, and as long as you're communicating with somebody in the US there's no extra charge.
Performance
The CellSpot excelled in my testing, both as a home router and as a device supporting Wi-Fi calling.
As a router, it actually outdid the Asus RT-AC68U by a small margin. This was likely because the RT-AC68U was tested in 2013 with older firmware.
On the 5GHz frequency band, at close range the CellSpot registered a sustained Wi-Fi speed of 571Mbps. When I increased the range to 100 feet, it scored 340Mbps. These are among the top Wi-Fi speeds I've seen.
CNET Labs 802.11ac 5GHz Wi-Fi performance
- Close range
- Long range
On the 2.4GHz frequency band, the CellSpot actually topped the charts with 250Mbps and 214Mbps for close range and long range, respectively. Like the RT-AC68U, the CellSpot had an effective range of about 200 feet. And it also passed my 48-hour stress test, in which it was set to move data between multiple Wi-Fi clients: during this time it didn't disconnect even once.
CNET Labs 2.4GHz Wi-Fi performance
- Close range
- Long range
Note that I tested the router at CNET's offices, where there are walls and many Wi-Fi devices that are out of my control. Generally, walls shorten the reach of a Wi-Fi signal, and other Wi-Fi devices create interference. As with all Wi-Fi routers, your results may vary depending on where you live.
As a Wi-Fi calling supporting device, the CellSpot was also excellent. Within its effective range, I was able to place calls and hold many long conversations without being disconnected. The call quality was basically the same as when I used a regular cell signal, though distortion was a bit more frequent. I also noted that Wi-Fi calling worked well even when the router was set to do other heavy tasks, including file downloading, and HD content streaming to multiple clients.
Note that Wi-Fi calling doesn't allow uninterrupted transition to a regular cell signal. This means if you place a call using Wi-Fi calling and then move away from the router, when the Wi-Fi signal is cut off, the conversation will be disconnected even when there is cell signal. This also happens the other way around.
Conclusion
T-Mobile's Personal CellSpot is a win-win device.
Though you don't need it to use T-Mobile's Wi-Fi calling feature -- most any router will do -- there's little reason not to get one, especially if you need a router for your home. Under the T-Mobile branding, this is one of the best home Wi-Fi routers on the market with excellent performance and great features. And the fact that it's basically free for standard T-Mobile users (the $25 deposit is refundable when you return the router) doesn't hurt.
But when you're done using data, the CellSpot is great for making calls, too. Sure, Wi-Fi calling has its drawbacks -- it can cause a lot of feedback on a conference line, for example, and voice quality can sound a bit off -- but it remains a convenient and effective way to get cellular service when you're off the network. That makes it a great accessory for T-Mobile customers.