SuperDroid Robots RS232 3-5V TTL Serial Converter Cable - No TTL Connector Female RS232 DB9 connector. The cable itself is 72 inches long. The cable works for 3.3V TTL signals and 5V TTL and requires 3.3.V or 5V power from the TTL side. The circuitry is built into the cable! The TTL cable end carries the Tx, Rx, CTS, RTS, V and Ground signals. This cable has NO TTL connectors, its just bare wire for your own connections.