Which bios interrupt provides serial port services andlist down names of 9 pins of db-9connector.

To help interrupt serial driven communications, the PC utilizes two interrupts, IRQ 3 and IRQ 4.

INT 0Bh and INT 0Ch are the BIOS interrupt

It patches the COM1,COM2 when you call the Com Init Intr routine: interrupt vectors (int 0Ch int 0Bh), allowing IRQ 4 and IRQ3 in the 8259A PIC.

IRQ 3  0Bh  Serial port 2

IRQ 4  0Ch  Serial port 1

9 pins of DB-9 connector -

1       RTS, Request to Send

2       CTS, Clear to send

3       GND,Ground

4       RXD,Receive Data

5      TXD, Transmit Data

6       DTR, Data Terminal Ready

7       DSR, Data Set Ready

8       RI, Ring Indicator

9       DCD,Data carrier detect

the answer to your question would be something called hertz. the unit of measurement called a hertz, which is one cycle per second, is used to measure clock speed. within one cycle, your computer processes, refreshes, or updates itself to the changes that it is going through. in the case of computer clock speed, one hertz equals one tick per second. the clock speed of computers is usually measured in megahertz (mhz) or gigahertz (ghz)