What to do about DTR, DCD, DSR pins

[ssshake]

Currently these pins are not connected and I believe people have reported problems with certain computers because of this.

I was talking to someone a few months ago and I forget who gave me the advice. That either all or a subset of these can be permanently wired to 5V off the USB power source.

I'm looking for advice on which if any to apply this to and if it's OK for all systems to always be high or if there needs to be a switch, jumped, solder pads to let people turn this off.

Data Terminal Ready DTE is ready to receive, initiate, or continue a call. DTR out in 20 4

Data Carrier Detect DCE is receiving a carrier from a remote DCE. DCD in out 8 1

Data Set Ready DCE is ready to receive and send data. DSR in out 6 6

Data Carrier Detect, abbreviated as DCD, or alternately Carrier Detect abbreviated as CD, is a control signal present inside an RS-232 serial communications cable that goes between a computer and another device, such as a modem. This signal is a simple "high/low" status bit that is sent "from DCE to DTE", or in a typical scenario, from the peripheral to the computer. It is present on virtually all PC serial ports - pin 1 of a nine-pin (DE9) serial port, or pin 8 over a 25-pin (DB25) port. Its purpose varies depending on the device connected, but the most typical meaning is to indicate when a modem is connected to another remote modem via telephone lines.

• This reads to me like maybe you would want the modem to report to the computer that it's connected to something. And perhaps making it always on would not be good. But if it's off it will never tell a computer that cares that it's connected to a remote host.

Data Terminal Ready (DTR) is a control signal in RS-232 serial communications, transmitted from data terminal equipment (DTE), such as a computer, to data communications equipment (DCE), for example a modem, to indicate that the terminal is ready for communications and the modem may initiate a communications channel.

The DTR signal is present on pin 20 of the 22-wire RS-232 interface using a DB-25 connector, and on pin 4 of a newer DE-9 serial port. The signal is asserted (logic "1") by raising the voltage of the pin from negative to positive. Dropping the signal back to its negative state indicates to the modem that the communications session shall be terminated.

• This reads to me like the computer is telling the modem it's ready. Our modem can always assume it's ready so I don't think there is any utility in this. The modem doesn't need this info and it's the computer which is supposed to be supplying it's status.

For DSR I don't think this is needed at all.

[ssshake]

After doing this bit of research it sounds to me like these shouldn't be considered, except for maybe DCD.

[deltecent]

DCD and DTR would be wonderful for using the modem on the BBS side. DTR is required to "hang up" the modem and DCD is required to know when someone has connected or has disconnected. RI would be nice, but probably not necessary.