Sony has finally launched the PlayStation TV outside of its homeland Japan. It is now available in the UK for £85 (and the States), but what is PS TV and why should you consider it over the multitudes of other set-top-boxes out there?

What if you don't own a PS4? Can it still be used as a games console or video streamer?

These are the questions we're asked regularly about Sony's latest device, so we've decided to answer them in one simple guide prior to the full review of the UK version when it arrives in the next few weeks.

PlayStation TV is a small set-top-box based on Sony's current portable gaming device, the PS Vita (indeed, it is called Vita TV in Japan). It plugs into a television and offers access to compatible Vita, PSOne and PSP games through the PlayStation Store or an included game card slot.

Its main screen is the same as the PS Vita's user interface, with icons for each application and service, and as well as games it provides access to video apps, enabling you to stream content to your TV in the same way as an Apple TV or Roku box, for example. Unfortunately though, the US version is strangely missing some of the bigger services on launch - such as Netflix - which are on the PS Vita, so we're currently not sure if they'll appear again by the time it hits the UK.

Sony's own video services are available, so you can rent or purchase movies for download.

Like the PS Vita, it can also be used to play PlayStation 4 games remotely, in another room. You link it to your PS4 and it will stream 1080p video of the game from the console itself and the control codes from an attached DualShock 4 or DualShock 3 controller back to the PS4. The lag is small and PS4 games run impressively, we found during a test at E3.

READ: Hands-on: PlayStation TV review

Although the PS4 remote streaming is one of the box's most impressive talents, you don't need a PlayStation 4 to use any of its other features.

As it can play PS Vita, PSOne or PSP games bought from the PS Store (or on game cards in the case of physical Vita titles) you can use it as a separate games console, albeit one without next-generation graphics or abilities.

That essentially means you get a capable games console for £85.

Because some PS Vita games require the use of the front touchscreen or rear touch panel of the portable device, they won't work on the PlayStation TV and are therefore not available in the PS Store for download. You are also advised to check their control methods if you are looking to buy the game card versions.

For example, recent smash Tearaway relies heavily in touch controls so will not be playable.

PSOne and PSP games didn't require touch controls so all those available to download will work.

To control the PS TV and play games on it you will need a PlayStation DualShock 3 (as used by the PS3) or DualShock 4 (PS4) controller. It is recommended that you use the latter if you plan to play PS4 games remotely, but if so, you will already have a PS4 controller in the home that you can use.

You will also be able to pair an existing PS3 controller with the box if you have one. Alternatively, you can buy either controller separately. In the States, a separate bundle is available that includes a controller and a few games. No UK equivalent has been announced as yet, though.

A HDMI cable comes with the PS TV, but if you want to download games immediately, there's only 1GB of storage space and many Vita games require far more than that. You are advised therefore to buy a separate PS Vita Memory Card, which start at around a tenner for a 4GB model, rising to £75 or more for a 64GB version.

The box does come with built-in Wi-Fi although if you want to play PS4 through the Remote Play feature it is very much recommended that you use the Ethernet port and a wired connection to your router. That way the performance levels will increase dramatically.

For all other functions, the Wi-Fi connection should suffice.

In the US, the public beta version of PlayStation Now is immediately available on the PS TV. Stateside users can access the cloud gaming service through the box.

READ: What is PlayStation Now and when can I get it?

However, it won't be available in the UK from launch as the service has not launched in the country yet. It is planned to appear in 2015 and will come to PlayStation TV when it officially launches.