1 A control signal that is used in a computer system is labe

1. A control signal that is used in a computer system is labeled DT/R for data transmit/receive. What action is implied when this signal is HIGH? LOW?
2. Assume you were troubleshooting a circuit containing a 4-input NAND gate and you discover that the output of the NAND gate
is always HIGH. Is this an indication of a bad gate? Explain your answer.

Solution

1 Answer When a serial connection is made between two computers using a null modem adapter, the DTR and the Data Carrier Detect (DCD) lines are typically paired. This allows both ends of the connection to sense when the connection is active. On many computer systems, including , the DTR line is held low while the serial port is unused and not being controlled by any applications.