Generic selectors
Exact matches only
Search in title
Search in content
Post Type Selectors

Reply To: 12/16Khz and reverse polarity


12/16 Khz signal is sent from Exchange to subscriber premises for around 100ms duration.
In reverse polarity signal potential(-48V) on a & b limbs are reversed momentarily(donot know exact dutration).
Both these signals are generally used to send metering pulses for different machines (One sensing pulses other sensing reversals)