Features Various Ports: Designed to have 5V, 3.3V, TXD, RXD and GND ports to satisfy your varied working needs, reliable and useful. Working Light: Comes with PWR, TXD and RXD indicators as well as reserved RTS and CTS positions for convenient operation. Better Design: 340 chip has wide compatibility, while the yellow pin header ensures easy installation and good durability. Has Long Line: A 50cm long cable is also attached to the USB to TTL serial adapter module, which enables firmer connection. Wide Matching: Supports for 98, for 2000, for XP, for Server 2003, for VISTA, for Server2008, for Win7, etc. Specification: Item Type: USB to TTL Serial Adapter Line Length: Approx. 50cm / 19.69in Function: USB to TTL Transfer Speed: 300 bps to 1.5 Mbps Port: 5V, 3.3V, TXD, RXD, GND Package List:1 x USB to TTL Serial Adapter Note:The industrial control board has TTL port, which can use a USB to TTL communication cable. Some systems are not compatible. You can use a USB to 232+232 to TTL communication cable. Package List 1 x USB to TTL Serial Adapter