Phone Microwave (Name; Phone Wave)#
| Designation | Future Gadget #8 |
| Common name | Phone Microwave (Name; Phone Wave) |
| Function | Converts text messages into a transmittable data packet sent to the past |
| Inventors | Rintaro Okabe, Kurisu Makise, Itaru Hashida |
| Housed at | Future Gadget Laboratory |
| Base unit | Modified consumer microwave oven |
| Payload medium | Bananas (early trials), text message metadata (later trials) |
| Effective range | Confirmed up to several decades; theoretical limit unknown |
| Known side effect | Localized worldline divergence |
| First success | Episode-linked to Episode 01 |
| Current status | Decommissioned after Steins Gate worldline was reached |
| Danger class | #lore Restricted-use |
The Phone Microwave, universally shortened to PhoneWave by lab members despite Okabe's insistence on its full parenthetical name, is Future Gadget Laboratory's eighth invention and the device responsible for the entire plot of the lab's involvement with SERN. It began as a failed attempt to fax organic matter and ended as the world's first confirmed D-Mail transmitter — a machine capable of sending short text messages into the past.
Its existence is the reason Kurisu Makise first crossed paths with the lab, the reason SERN dispatched surveillance and worse, and the reason Daru still refuses to eat bananas that have gone soft in a microwave. See episode-guide for the episode-by-episode fallout.
The PhoneWave began life as an ordinary microwave oven purchased secondhand for the lab's kitchenette. Okabe — convinced that "phone" and "microwave" sounded like a suitably mad-scientist combination — rewired it to accept a mobile handset docked in its drum, with the stated goal of transmitting matter as a fax machine transmits paper. Early trials only succeeded in liquefying bananas into a green paste the lab nicknamed "Gel Banana," a #stub result that nonetheless proved something was crossing between the microwave and the handset.
The breakthrough came after Kurisu joined the lab and picked the device apart. Her analysis reframed the gel bananas not as a failed teleportation but as a partial success: the microwave wasn't moving matter through space, it was scrambling a message through time. Once the lab stopped trying to send solid objects and started sending SMS text instead, the results became reproducible. Okabe rebranded the successful configuration a "D-Mail," and the age of retroactive causality began.
The PhoneWave does not "send" a message across time in any conventional sense; it re-encodes a signal so that it destructively interferes with itself along a closed timelike loop, arriving at the receiving handset before it was sent from the transmitting one. The mechanism piggybacks on microwave-band emissions and a commercial mobile phone's transceiver — which is why an unmodified IBN 5100-class capacitor bank was later added to stabilize the packet once payloads grew longer than 148 characters.
graph TD;
PhoneMicrowave-->DMail;
DMail-->PastHandset;
PastHandset-->WorldlineShift;
The stored energy required for a single transmission is modest by laboratory standards. Treating the discharge capacitor as an ideal capacitor of capacitance $C$ charged to potential $V$, the energy budget is
$$E = \frac{1}{2}CV^2$$
which the lab measured at roughly 40 joules per successful D-Mail — enough, Daru joked, "to toast half a bagel, or unmake a friendship."
Functions as an unremarkable microwave oven. Used daily by lab members for lunch, with the explicit house rule that nothing metallic goes in the drum while the phone dock is active — a rule broken exactly once, memorably.
The docked handset receives a call routed through the internal modem. If the call connects to a phone that existed in the past, the audio (later, SMS text) reaching that older handset becomes a D-Mail. The sender hears nothing; there is no dial tone, no ring — only silence and, later, a notification on a phone that already existed.
Interrupting a transmission mid-cycle — by removing the handset or cutting power — produces the Gel Banana effect on whatever is in the drum. The lab keeps a running, unfunny tally.
Every confirmed D-Mail shifted the observed reading by a measurable amount. The lab's early messages were sent with no understanding of how small a change could cascade — see alpha-worldline and beta-worldline for what happens when it does.
A partial, reconstructed log of transmissions lab members can corroborate. Sortable by column.
| Date sent | Sender | Nominal recipient | Content summary | Divergence shift |
|---|---|---|---|---|
| — | Okabe | Lab phone (past) | Bar quiz trivia rewrite | 0.000341 |
| — | Kurisu | Her own past phone | Correction to a public statement | 0.001220 |
| — | Daru | Convenience store phone | Lottery number test (aborted) | 0.000009 |
| — | Unknown | Lab landline | Warning message, contents disputed | 0.021557 |
| — | Okabe | Lab landline | Rewinds a lab member's death | 0.081609 |
| — | Okabe | Lab landline | Reverses the above rewind | 0.081609 |
Repeated use showed that memories of the "old" worldline can persist in some individuals even after a shift — a phenomenon later formalized elsewhere as a Reading Steiner-type effect. The lab does not fully understand why some members retain memories and others don't; kurisu's notes on the subject remain incomplete. #lore
The device is permanently installed on the second floor of the lab, bolted to the same workbench where the divergence meter sits. For a general treatment of domestic microwave ovens (the mundane, non-time-traveling kind) see Microwave oven.
Related devices: Time Leap Machine (the PhoneWave's successor once memory-only transmission became possible) and D-Mail for the messaging theory itself. Some lab visitors have asked about a hypothetical voice-only variant; no such Mark II was ever built.12