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DCD interaction - Printable Version

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+---- Thread: DCD interaction (/showthread.php?tid=434)



DCD interaction - admin - 12-31-2017

Since the WiModem232 is the only WiFi modem available that controls ALL of the RS232 lines, there has been a few situations now that have come up where the terminal program and/or hardware are not properly setup for dealing the DCD.

By default, DCD changes states when a connection is made.  This means that if a terminal program or interface card are looking for a change of the DCD line they are going to see it.  So, you need to make sure that the state change does what you want it to do!

You can change the polarity of DCD (which way it toggles) using the AT*D command.  You can change how DCD is handled using the AT&C command.  AT&C1 is the default, and it means to change the DCD line based on the connection state.  So, when a connection is made it changes states from low to high (or high to low, depending on the polarity setting with AT*D).  AT&C0 always enables the DCD line and will never change states when a connection is made.

Look at your terminal program's manual (and hardware manual if you are using a serial card) to determine what happens when DCD changes states.