OnePlus' latest models support 5G. In fact, the official names of the OnePlus 9 5G and OnePlus 9 Pro 5G end with 5G. So, if a 5G network is available in your area, you would expect to be able to activate either new device and connect to the wireless carrier's 5G network.

The reality is a bit more complicated.

In the US, both the OnePlus 9 and the OnePlus 9 Pro work fine on one carrier's 5G network, but not at all on another. This situation is bound to frustrate prospective buyers of the OnePlus 9 and OnePlus 9 Pro.

Here is what we know about the OnePlus 9 and 5G and our own experience testing this phone.

Both the OnePlus 9 and OnePlus 9 Pro are powered by Qualcomm's Snapdragon 888 silicon. This system-on-chip includes Qualcomm's X60 modem, which OnePlus says can achieve faster 5G speeds by combining FDD (frequency division duplex) and TDD (time division duplex) frequency utilization technologies using carrier aggregation. This means that both OnePlus 9 models should be able to support the latest 5G networks being built by wireless carriers now and in the years ahead.

But there is more to 5G connectivity than cellular modems. Smartphones must also support the same bandwidth used by wireless carriers. And in the case of the new OnePlus 9 model, a check of the supported bands revealed that different U.S. phone carriers have different levels of support.

OnePlus actually posts this information on its website: go to the OnePlus 9 pre-order page (or the OnePlus 9 Pro pre-order page) and click on "Check carrier compatibility" AT&T, T-Mobile, Verizon, and AT&T.

OnePlus' list shows extensive 5G band support for T-Mobile and 5G bands used by Verizon; nothing is listed for AT&T.

Put another way, if you buy a OnePlus 9 or OnePlus 9 Pro, it will work on T-Mobile's 5G network. (This is to be expected, as T-Mobile is selling the phone directly and has begun taking pre-orders ahead of the phone's April 2 arrival in stores.) At launch, OnePlus says it will only work on AT&T and Verizon's LTE networks.

This makes sense for AT&T, since neither the OnePlus 9 nor the OnePlus 9 Pro support the same carriers' 5G bands. But what about Verizon, since the OnePlus 9 phones work on that carrier's bands? Shortly after the new phones were announced, all OnePlus could tell us was that it was working with Verizon to certify the OnePlus 9 and OnePlus 9 Pro on Big Red's network.

That work paid off, and Verizon and OnePlus have since announced that the unlocked phones will work with Verizon's 5G, albeit with some caveats. According to the announced 5G support for the OnePlus 9, the Pro version of the phone will work on both the nationwide 5G network and Verizon's high-speed ultra-wideband network, which is located in more than 60 cities.The OnePlus 9 apparently only works on the nationwide network and does not appear to work on ultra-wideband.

This is consistent with our experience testing the phone. My colleague Jordan Palmer was able to connect to Verizon's nationwide 5G network while testing the OnePlus 9 Pro. Verizon's 5G network is slower than the speeds expected of 5G because it is built on a lower frequency band. We were unable to test the OnePlus 9 Pro on Verizon's faster Ultra Wideband network.

I tested the OnePlus 9 with a T-Mobile SIM card and had no problems connecting whenever the carrier's 5G network was available. Of course, the speeds I got on T-Mobile's 5G were actually slower than the LTE speeds of other carriers in the same area. That's the reality of 5G at this point.

When a major flagship phone like the OnePlus 9 comes out, the question "Will it work with 5G?" should receive a simple yes/no answer, rather than a series of raised eyebrows and cautionary notes.

Phone carriers and device manufacturers deserve credit for the progress they have made regarding 5G. However, for people to be convinced that the 5G future has arrived, it is essential to make cell phone compatibility a clear part of the cell phone buying experience.