RTS and CTS; polarity and handshaking

[echristopherson]

How do the RTS polarity, CTS polarity, and and RTS/CTS handshaking mode options (AT*Rx, AT*Cx, and AT&Kx) interrelate? There are eight possible combinations, but I'm wondering if all of them are meaningful; and which ones are good for which problems or situations.

[admin]

The default polarities are for standard Commodore based software, which is backwards from standard devices. The polarities can be changed if the driver needs it, like the V1541-38400 driver.

[echristopherson]

The default polarities are for standard Commodore based software, which is backwards from standard devices.  The polarities can be changed if the driver needs it, like the V1541-38400 driver.

OK, so the RTS and CTS polarity would *both* be flipped if you decided to do that, correct? Does that relate to the handshaking style at all?

Finally, I noticed after I posted that there's another polarity option -- I think it was DCD but I'll have to wait until I leave work to find out for sure. What does that do?

[admin]

You can change the polarities as needed. Some devices might need positive polarity for RTS, but not for CTS. Same with the handshaking flag.

DCD is data carrier detect. That is used for the carrier detection (when a connection is made to a URL). That too, can be inverted.

The default settings work with all standard CBM terminal programs. You only need to change polarities if you are using a custom driver that adheres to standard RS232 logic.