Verizon may have been getting buzz for turning on its mobile 5G network last week in Chicago and Minneapolis, but AT&T isn't letting it keep the spotlight for long.

On Tuesday the nation's second-largest network announced that it has started turning on its mobile 5G network in "parts" of seven more cities: Austin, Los Angeles, Nashville, Orlando, San Diego, San Francisco, and San Jose.

With the seven new areas, AT&T ups its mobile 5G city count to 19, a decent headstart on coverage compared to its rivals. Unlike Verizon, however, users in these areas are currently not able to use any 5G phones on the new network.

So far AT&T only offers one 5G device, the Netgear Nighthawk 5G mobile WiFi hotspot. Like the other carriers it will offer Samsung's new Galaxy S10 5G, but that device won't come to the carrier until later this spring.

AT&T promises a second 5G Samsung phone will arrive later in the year.

Verizon currently offers a "mod" accessory that will turn last year's Moto Z3 into a 5G phone. It will also be the first to offer the Galaxy S10 5G. Noted phone leaker Evan Blass recently tweeted that Verizon will get that Galaxy on May 16.

Sprint, which turns on its 5G network in Chicago, Atlanta, Dallas and Kansas City in May, will launch with LG's new V50 ThinQ 5G.

Meanwhile, T-Mobile will launch a 5G network in the first half of the year as well, but it has yet to announce exact timing or launch cities.

Verizon 5G:Verizon turns on mobile 5G network ahead of schedule in Chicago and Minneapolis

T-Mobile 5G:After report of delay, T-Mobile says its 5G network plans are still on track

Sprint 5G:Sprint's 5G network will go live this May in Chicago, Atlanta, Dallas and Kansas City

Unlike the "5G E" logo that is increasingly appearing on more 4G LTE AT&T phones, including recent Galaxys and iPhones, this new network is based on what is accepted as actual 5G, complete with the promised faster speeds and lower latency, the latter a measure of network responsiveness.

Last December, AT&T turned on mobile 5G in its first 12 cities, though the company has yet to elaborate on if it will be changing its 5G pricing. When it launched in December it charged $70 per month for 15GB of 5G hotspot data.

Verizon, meanwhile, is charging an additional $10 for 5G access for phones, assuming you have one of its latest unlimited data plans. The carrier is also waiving the fee for the first three months as it builds out its new network.

Why you will want to wait

As with AT&T's first dozen cities, and the new networks from Verizon and T-Mobile, AT&T's current 5G network is based off a technology known in industry jargon as "mmWave," or millimeter wave. While this network promises super fast speeds, coverage will be much more limited, particularly at launch.

Verizon's mmWave network, for example, is only in a handful of locations in Chicago and Minneapolis and AT&T is making it clear that today's launch will only have 5G live in "parts" of its own new cities.

A second 5G technology, known as "sub-6," will be rolled out by AT&T later this year and should provide a much larger, more consistent coverage area and can work in tandem with today's mmWave network.

AT&T calls mmWave "5G+" for its faster speeds, referring to its larger "sub-6" network as simply "5G."

The first phones and devices, such as that Galaxy S10 5G, only will be capable of connecting to the mmWave 5G network. They lack the necessary chip to tap into the larger "sub-6" network that is coming and prevent you from getting the full 5G experience.

AT&T's second Samsung 5G phone that is due out later this year will, however, support both mmWave and sub-6 making it, for most people, the likely first 5G phone worth to wait for.

Follow Eli Blumenthal on Twitter @eliblumenthal