Minicom and serial communications

The mode line "online-offline" on minicom has some information overload built in that is confusing, but when you know about it can be very useful and help with the setup in your situation.

If you have a DCD line between your remote device and the serial port, which is detected by minicom or indicated to exist according to your configuration, the mode line will indicate status of the DCD signal in lower case. However, if you are configured to use something like a 3 line RS-232 cable with no control signals at all, minicom will use an internal simulation of the DCD status, and will print to the mode line in upper case. It will change the mode line to ONLINE only if it can detect that you have enabled the remote device, or in some other way recognizes that you do have a live link.

The essense of the above is that if you have a non-modem device on a serial port and do *not* use the DCD line, the status line will always say "Offline", by default. If you set the configuration to indicate no DCD line, it will say "OFFLINE" unless you use a successful dial command to enable your remote device.

It's quite useful, *if* you know about it...

Configuring minicom can be confusing, as it will appear to change the parameters when it actually does not. Here is a sequence that I've posted a few times before to explain just exactly how to configure minicom. Of course, you will have to get the configuration right, which depends on many factors you have not mentioned.

1) su to root.

2) Invoke "minicom -s".

3) Get the "configuration" menu by typing in two characters, ^A and then O.

4) Position the highlight on the menu list by using the up or down arrow keys and type a

5) You may not need to change anything in the first two areas listed, "Filenames and path" and "File transfer protocols". But look at them to see what options are available, for future reference. You do want to set the appropriate entries in "Serial port setup" and in "Modem and dialing" where at least you want to delete all of the modem init strings to avoid sending them at start up. "Screen and keyboard" probably do not need any changes.

6) Save the settings to either default, or to some named configuration, such as "port0" or perhaps use the device's name.

7) Exit minicom.

8) Exit root.

9) Invoke minicom, as "minicom" to get the default config, or as "minicom port0" to get the port1 configuration.

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