user37085: The usb to serial converter i found was $4 .maybe i could use something less expensive,like jus a port.I need serious help ,the serial port was about $1

user36749: May I suggest RS232 connection? It is an ancient tech but it might work for you. I am adding a tutorial. Also a component from eBay, which is 0.99 US dolar.  

37085: <p>The usb to serial converter i found was $4 .maybe i could use something less expensive,like jus a port.I need serious help ,the serial port was about $1</p>
 36749: <p>May I suggest RS232 connection? It is an ancient tech but it might work for you. I am adding a <a href="http://www.arcelect.com/rs232.htm" rel="nofollow noreferrer">tutorial</a>. Also a <a href="http://www.ebay.com/itm/MAX232CSE-Transfer-Chip-RS232-To-TTL-Converter-Module-COM-Serial-Board-AD-/112071858489?epid=1586990854&amp;hash=item1a1800d939:g:GrcAAOSwOtdYTeid" rel="nofollow noreferrer">component</a> from eBay, which is 0.99 US dolar.  </p>
