SECTION 6. 9-PIN SERIAL INPUT/OUTPUT

 

 

 

22

RI

I

Ring Indicator: The

7

SG

Signal Ground: Voltages

 

 

 

modem raises this line to

 

 

are measured relative to

 

 

 

tell the terminal that the

 

 

this point.

 

 

 

phone is ringing.

 

 

 

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