Connectors for a RS485 multipoint bus

I guess you have triple-checked the baud rates between the microcontrollers, as well as between receive uart1 and the hyperterminal.

The receive code is not correct:

    while(1)
        {
            uart1str(uartrec4());  //printing received uart4 data in hyperterminal
            Delayms(1000);
        }

Problem here is that uartRec4 receives one character. What happens is:

• sender sends out 7 bytes, waits one second
• receiver receives the first byte, send it out, then ignores everything for 1 second.

Remove your delayms(1000) from the receiver side. Ensure that you're using the same bandwidth both between pics and also on hyperterminal.

If still not work, try to split into parts:

• make a "receiver" side which does not receive anything just prints Hello to uart1 - this checks if you have everything correct towards the PC
• send only one character, e.g. an A on the sender, wait 1000ms and repeat - this does not require any buffering and special timing consideration.

Note that uart1str(uartrec4()) can also be problematic if the hw uart does not have a buffer (PICs do have a 2 byte receiver buffer, afaik). (The problem is that you're waiting for one byte, then while sending it out to uart1, another byte may arrive which you supposed to check for.)

If your computer doesn't support RS485 protocol, and if we're talking about regular PC's it most probably doesn't, then you cannot directly connect A and B to serial port. I would suggest using an USB-RS485 converter.