Hi!
I want to transmit and receive data on serial port (currently i'm working on a single PC with its Tx and Rx pins short). I'm using following program (in Turbo C), but to no use. Can anyone help me out with this code?

#include <bios.h>
#include<stdio.h>
#include<iostream.h>
#include <conio.h>
#define COM1 0
#define DATA_READY 0x100
#define SETTINGS ( 0xE0 | 0x08 | 0x00 | 0x03) //(baud_9600 | ODD_PARITY | COM_STOP1 | COM_CHR8)
int main(void)
{
clrscr();
int out, status;
char in,x;
bioscom(0, SETTINGS, COM1); /*initialize the port*/
cprintf("Data sent to you: ");
while (1)

{

status = bioscom(3, 0, COM1); /*wait until get a data*/
if (status & DATA_READY)
if ((out = bioscom(2, 0, COM1) & 0x7F) != 0) /*input a data*/
{
cout<<"the data received is "<<out<<endl;
putch(out);
}
if (in=getch())
{ cout<<"key was pressed"<<in<<endl;
if (in == 27) /* ASCII of Esc*/
{
break;
}
else
{cout<<"we are aobut to transmit"<<endl<<in<<endl;
bioscom(1, in , COM1); /*output a data*/}
}


}
return 0;
}


Thanx

 

Please help me

 

Most PCs that I've used have had hardware handshaking set on by default.

I guess you've connected the RX pin 2 to the TX pin 3 on the 9-pin serial port, is that right?

Try also connecting pin 4 DTR to pin 6 DSR to enable the handshaking.

 

I've tried by shorting Pin 6 and 4 as well, but it didn't work.
I wonder if the code is correct. Please give it a look.

 

I've never personally used bioscom to talk to the ports but this looks right, as compared to another example of code I found that does use bioscom.

Are you sure you're connecting to COM1? Some computers have several serial ports;
maybe your loopback is plugged into COM2.

When you first call bioscom to connect to the port, does it return a status telling you whether it succeeded or failed? It might be good to get and print a return status; maybe the initial open is failing.

Another thing you could do is try a terminal program like HyperTerminal or TeraTerm to do the same thing - that might help verify which COM your connector is mapped to, and can help test your loopback plug.