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A common Skynet tactic is to have a Terminator impersonate another human or Terminator's voice or appearance.

Most Terminators seem to have the ability to perform vocal impersonations. Terminators utilizing mimetic polyalloy - including the T-1000 in Terminator 2, the T-X in Terminator 3, and the T-1001 in Terminator: The Sarah Connor Chronicles - are able to impersonate both the voice and the appearance of other humans.

Vocal impersonation

Vocal impersonations have been used in all four Terminator films and the TV series:

The T-800 did a vocal impersonation of Sarah Connor's mom while talking to Sarah. While doing the impersonation, the T-800 was able to convince Sarah to give her the phone number of the Tiki Motel. The Terminator

The T-800 did a vocal impersonation of a police officer (L119) during pursuing Sarah Connor. The Terminator

The T-800 did a vocal impersonation of John Connor while talking on the phone to the T-1000, who was simultaneously impersonating Janelle Voight. Terminator 2: Judgment Day

The T-RIP impersonated Kyle Reese's voice in order to draw out John Connor. Terminator Salvation

Cromartie used Sarah Connor's vocal impersonations on the phone.pilot episode

Cameron used John Connor's vocal impersonations to fool Cromartie in the episode pilot episode and fool Riley Dawson's foster father in "Ourselves Alone".

Mimetic polyalloy impersonation

The physical impersonation strategy has been used in Terminator 2: Judgment Day, Terminator 3: Rise of the Machines, and Terminator: The Sarah Connor Chronicles. It was not used in The Terminator, as mimetic polyalloy Terminators had yet to be sent back in time, nor in Terminator Salvation, as mimetic polyalloy Terminators had yet to be built.