Time-assignment speech interpolation

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In telecommunication, a time-assignment speech interpolation (TASI) is an analog technique used on certain long transmission links to increase voice-transmission capacity.

Note: TASI works by switching additional users onto any channel temporarily idled because an original user has stopped speaking. When the original user resumes speaking, that user will, in turn, be switched to any channel that happens to be idle. The speech detector function is called voice activity detection.

Source: From Federal Standard 1037C and from MIL-STD-188

TASI was invented by Bell Labs in the 1960s to increase the capacity of Transatlantic telephone cables. It was one of their first applications requiring electronic switching of voice circuits.

Later Digital Circuit Multiplication Equipment included TASI as a feature, not as distinct hardware.