# RS232 to TTL converter problem

I have a RS232 to TTL Converter which has 4 pins Vcc, Tx, Rx, GND . I am trying to make a serial communication with my PC. I have a AVR development board and I have tested my program by connecting UART to USB cable to development board and my PC and is working. But when I connect jumper wires tx to rx of and rx to tx of converter and vcc to 5v and gnd to gnd then it wont work. I dont know where is the problem. Is my converter has some problem. Please help

• Try connecting 0v and 5V to your circuit with power on it, and then connecting Tx and Rx together (not to your AVR). You should see a local echo on the computer terminal program, only when Tx and Rx are shorted together. – tomnexus Aug 13 '15 at 5:41
• @tomnexus I shorted the Tx Rx pins of connector, applied 5v to vcc and gnd to gnd but i dint receive any local echo. BTW what is this local echo. I have noticed something new, when i connect one end of jumper wire to Tx and other end to nothing then a series of NULL comes in docklight, – Aircraft Aug 13 '15 at 5:51
• @tomnexus I have shorted the Tx RX and when ever I type something it gives me back on termnal. Is this local echo? – Aircraft Aug 13 '15 at 5:57
• Yes, that is local echo. You said "tested my program by connecting UART to USB cable to development board and my PC and is working." So what is not working? How is the new setup different than what was working? – tcrosley Aug 13 '15 at 9:21
• By that line I mean to say that I have a UART port on my dev. board and I connected a UART to USB cable and my program is running but when i connect individual rx tx pins from dev. board to converter, then its not working – Aircraft Aug 13 '15 at 10:06