From Intellivision Wiki
|Instruction Name||Terminate Current Interrupt|
|CP1610 Clock Cycles||4|
Terminate Current Interrupt. This instruction pulses the TCI output of the CPU. It appears the purpose of this line is to interface to an external interrupt controller. The Intellvision does not connect this line to anything useful, and so the TCI instruction appears to have little or no use on the Intellivision.