Synchronization

Synchronization refers to the process that connects a pilot and their Evangelion, allowing the pilot to activate and pilot the Evangelion. This process occurs while the pilot is inside the Entry Plug after the plug has been inserted through the back of the Evangelion's neck, although during harmonics tests, Test plugs and Simulation bodies are used along with the Evangelion. Upon synchronization, a neural connection is made between the pilot (and possibly the soul within) the Evangelion, allowing the pilot to not only move the Evangelion, but physically feel what the Evangelion feels. This form of feedback causes the pilot to also feel pain when pain is inflicted upon the Evangelion, and in extreme cases, physical manifestations of the pain can be seen.

Synchronization usually follows in steps, monitored and controlled by the Nerv personnel, although it appears that synchronization can be initiated without external aid, at least in the case of Evangelion Unit-02, which is operated independent of Nerv by both Shinji Ikari and Asuka Langley Soryu in Episode 08. Shinji synchronizes independently in Episode 18 again. The process used in Episode 01 to synchronize Shinji and Evangelion Unit-01 is as follows:

Man A: Roger. Inserting entry plug.

Woman: Direct hydro-transmission system, connection prepared.

Man A: Plug fixed in place.

Man B: First stage connection initiated.

Maya Ibuki: Filling the entry plug.

Man A: Connecting main power.

Maya Ibuki: Commencing secondary contacts. A-10 nerve connection, normal.

Ritsuko: Set the thought configuration to Japanese. All preliminary contacts established.

Maya Ibuki: Bi-directional circuits are open. Synchronization rate at 41.3%

Evangelion Unit-02's activation in Episode 08, reveals that synchronization is dependent upon the language in which the pilots think. Shinji thinks in Japanese, and Asuka in German, causing a system error and forcing Asuka to restart with the language set to Japanese. What language has to do with synchronization is not further explored or elaborated. Asuka's mother and the soul of Eva-02, Kyoko Zeppelin Soryu, was bilingual in German and Japanese and should have had no difficulty understanding both languages. This suggests that additional equipment within the Evangelion aids in synchronization as an intermediary (Possibly being bypassed during periods of extremely high synch rate or when the Eva goes berserk). Another possible instance of such a system being used is in Episode 03, where Eva-01's synaptic commands are looped for a short period.

Synchronization
Shinji synchronizing with Evangelion Unit-01 in Episode 01

It is believed that the Interface Headsets used by the pilots either are required or greatly enhance synchronization. These are always worn by the pilots within their entry plugs. Also of significance is the A-10 nerve connection which may indicate that the pilots are actually synchronizing with the souls within the Evangelion (the soul of the pilot's own mother) as much as with the Evangelion itself. In an interview with Yoshiyuki Sadamoto, he states that:

“

I was watching the NHK [public TV channel] program "Brain and Heart" and learned about the existence of the A10 nerve, and I told Anno about the idea that popped into my head at that time. That was the idea where "the dead mother is inside the robot, which is operated by mental/psychical bonding with the child."

„

The bond that Sadamoto mentions may have been represented by synchronization, which would imply that there is synchronization between the pilot and the soul within the pilot's Evangelion. This is a possible (partial) explanation as to why Asuka was not able to synchronize with Evangelion Unit-02 toward the end of the series as Kaworu states in Episode 24 that "soul has shut itself away for now."

Synch Rate

The Synchronization Rate, or just Synch Rate, refers to the degree of synchronization achieved; the higher the synch rate, the better the synchronization between pilot and Evangelion is. Presumably, higher synch rates result in better control but an increased risk in physical harm for the pilot. The synch rate, although ultimately limited by the pilot's own abilities, can be controlled (remotely) by the Nerv personnel. In Episode 18, Rei Ayanami was at risk of physical injury when attacked by Bardiel. Fuyutsuki gives the command to immediately lower the synch rate to 60%, but was belayed by Gendo's command to disconnect Evangelion Unit-00's infected arm, ultimately causing Rei great distress as she was still synchronized.

It is possible for the synch rate, which is reported by a percentage, to exceed 100%. In Episode 19, Shinji achieved a 400% synch rate during the battle with Zeruel resulting in him disembodying into LCL within the entry plug. His soul became trapped inside Eva-01. There are also other dangers when synchronized, causing mental trauma or mental contamination.

Eva-02's synch graph
Eva-02's synchronization rate jumping in Episode 08. (The markings on the bottom go below zero)

Notes

• In Episode 01, Misato says that it took Rei seven months to synchronize with her Evangelion
• In Episode 01, Shinji's first time synchronizing with an Evangelion, Maya reported his synch rate at 41.3%.
• In Episode 14 during the cross-synch tests between Rei and Shinji, Rei is reported to have nearly the same synch rate with Eva-01 as with Eva-00, however, Shinji's synch rate with Eva-00 is lower than with Eva-01.
• In Episode 16, Shinji exceeded Asuka's synch rate with their respective Evangelions, ousting Asuka from the highest synch rate holder. Rei remained the lowest amongst the three.
• In Episode 22, Ritsuko says that the synch rate isn't affected by superficial physical conditions.
• By Episode 22, Asuka's synch rate had been dropping and reached a level just above the activation level. By Episode 23, her synch rate is at single digits (she could not move her Evangelion) and by Episode 24, it's zero. She recovers her ability to synchronize with Eva-02 during Episode 25'.
  • Her final synchronization with the Eva appears to have been at an extremely high synch rate, lower than the border needed to dissolve her body but high enough for her to sustain actual physical damage from the Eva's wounds.
• In Episode 24, Misato says that Kaworu is able to arbitrarily set his synch rate to any level.