Following news of AT&T's imminent voice-over-LTE launch, Verizon is reminding people it's not too far behind. And, unlike its competitor, it says it will launch VoLTE nationwide with several handsets and video calling from the off.

It has yet to set the launch date, but a Verizon spokeswoman writes in a blog post that it will be coming in the next few months and will be a national rollout with a "tangible volume of handsets." (See VoLTE: So Close You Can Hear It and Verizon Promises Voice-Over-LTE in 2014.)

AT&T Inc. (NYSE: T) is launching VoLTE in select parts of four states on one handset tomorrow and is planning to do a market-by-market rollout after that. (See AT&T Confirms VoLTE Launch in 4 States.)

Light Reading learned back in July that between AT&T and Verizon Wireless , one would launch with just circuit-switched parity and the other would have a richer voice experience. Verizon is now answering the question of which is which, and the more robust rollout could explain its many delays with 4G voice. (See Shades of VoLTE.)

The Verizon spokeswoman says the service will support HD voice using the AMR-wideband standard and support video calling, including making and receiving video calls directly from the contact lists and the ability to switch from voice-only to a video call. She says that more Rich Communications Services are still to come, including large file transfer, robust group messaging, and location sharing.

Since Verizon is launching video calling, it only seems appropriate to look back at its journey to get to this point through videos. In the following video from Alcatel-Lucent (NYSE: ALU), Bill Stone, Verizon's executive director of network, brags about completing the first VoLTE call on the carrier's commercial LTE network back in March of 2011. (See Ericsson, Samsung, Verizon Try VoLTE.)

Of course, let's not forget that Stone also told us at that time that it would have VoLTE deployed in 2012... (See MWC 2011: Verizon Plans VoLTE for 2012.)

Just over two years later the carrier announced it had substantially completed its 4G LTE network rollout, having launched its 500th market, which was really the turning point that allowed it to focus on launching VoLTE. As a CDMA operator, Verizon falling back to 3G when its customers go out of a 4G zone is much more complicated than switching back to a GSM network. Verizon Wireless' Chief Network Officer Nicola Palmer explained what the network milestone meant for the operator in the following video from June 2013. (See Qualcomm Makes First VoLTE-to-3G Hand-Off.)

And, if you need a refresher on what VoLTE is, how it works, and why, Spirent Communications plc posted this thriller back in 2012 to break it all down.

— Sarah Reedy, Senior Editor, Light Reading