cleartosend

Clear to Send, often abbreviated as CTS, is a hardware flow control signal used in serial communication. It is part of the RS-232 standard, a widely adopted specification for serial data transmission. The CTS signal indicates that the receiving device is ready to accept data from the transmitting device. When a device asserts CTS, it is signaling that its buffer is not full and it can receive more information without losing any data.

CTS works in conjunction with the Request to Send (RTS) signal. Typically, the transmitting device asserts RTS to indicate that it wants to send data. The receiving device then checks its readiness and, if it can accept data, asserts CTS. This handshake mechanism prevents data loss by ensuring that the sender does not transmit data faster than the receiver can process it. If the receiver's buffer becomes full, it de-asserts CTS, signaling the sender to pause transmission until data can be processed.

The implementation and usage of CTS are managed by the hardware controlling the serial port. Software applications interact with these hardware signals through device drivers or direct port access. While CTS is a fundamental component of reliable serial communication, especially in older systems, modern communication protocols often employ software-based flow control or higher-level error correction mechanisms. However, CTS remains relevant in many embedded systems, industrial automation, and legacy equipment where direct hardware control is essential.