The D-Dial or sometimes called The Dial is a special device invented by Lala Satalin Deviluke. Like a standard phone, she can use it to call other people. But unlike a standard phone, it uses dimension technology that contains her inventions which she uses to "call" upon them. She has also made copies for her sisters. When a D-Dial malfunctions, it has shown to randomly summon objects from the user's virtual space into the real world.
The original user of the D-Dial was Lala, being its inventor. It first appeared in Chapter 1 of the To LOVE-Ru series when Lala used it to summon Vacuum-kun (a giant vacuum that has eight tentacles and has a much stronger sucking power than a regular vacuum) against Zastin, Maul and Smutts. Later on, it is revealed that she had already created other versions of her D-Dial for Nana and Momo, who use them to call upon animals and plants respectively.
In Lala's version, her D-Dial can summon her inventions she has created from a virtual space into the real world.
Like the original D-Dial, Nana's D-Dial can also summon from the virtual space within it. Instead of gadgets, Nana's D-Dial lets her summons animal friends she's met from other planets. She teleports her animal friends from her cyber safari park, a large virtual ecosystem where her pets may live in environments close to their home worlds.
Like the previous D-Dails, Momo's D-Dail can also summon from the virtual space within it. Momo's D-Dial lets her summon plant friends she's gathered from other planets. She keeps many different plants in her botanical garden in virtual space, and when she calls and teleports them, they may appear and grow immediately out of the ground, or may grow right out of her D-Dial.
Rito Yuuki's Mobile Phone Edit
In To Love-Ru Darkness side story 12, Lala rebuilds Rito's broken mobile phone. But instead of access to a virtual space, Lala instead improves the voice quality to make the listener "feel good". As a result, Rito's voice sounds so charming, it literally arouses sexual pleasure into the listener. The first "victim" of Rito's phone call was Yui, who endured both Rito's sexually pleasing voice and the unintentional sexual innuendo in their conversation, until she passed out in exhaustion. Rito then tested his phone by speaking to Momo on her D-Dial, and Momo collapsed in a second.