ISRO | ISRO CS 2013 | Question 36

The voltage ranges for a logic high and a logic low in RS-232 C standard is
(A) Low is 0.0V to 1.8V, High is 2.0V to 5.0V
(B) Low is -15.0V to -3.0V, High is 3.0V to 15.0V
(C) Low is 3.0V to 15.0V, High is -3.0V to -15.0V
(D) Low is 2.0V to 5.0V, High is 0.0V to 1.8V


Answer: (C)

Explanation: In the RS-232 standard a logic high (‘1’) is represented by a negative voltage – anywhere from -3 to -15V – while a logic low (‘0’) transmits a positive voltage that can be anywhere from +3 to +15V.

Option (C) is correct.

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