## Input/Output Device Driver Reference

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### DTR and RTS

This is the value of the modem control signals Data Terminal Ready (DTR) and Request To Send (RTS) put out by the communications hardware. Each signal is controlled independently and can be either ON or OFF. See IOCtls ASYNC_SETMODEMCTRL and ASYNC_GETMODEMOUTPUT, which can be found in the OS/2 Physical Device Driver Reference.

Initial Value When the physical device driver starts the port during device driver initialization, their values are turned OFF.

First Level Open The signals are normally turned ON, but there are many conditions that can cause the signals to be affected differently. See IOCtls ASYNC_SETMODEMCTRL and ASYNC_SETDCBINFO, which can be found in the OS/2 Physical Device Driver Reference, for a complete explanation.

Close Considerations A Close request packet causes DTR and RTS to be turned OFF after the transmit hardware has completely transmitted all the data sent by the physical device driver. After processing this Close request, the port is no longer open from another OPEN without a CLOSE. In addition, at least 10 additional character times must have elapsed (or one second, whichever is less).

Mode Utility Not applicable for direct control. Indirect effects through altering processing modes of the physical device driver are possible.