MKOB telegraph loop
The following diagram depicts the telegraph loop implemented by the MKOB program, from the users point of view. For more detail on how data flows within the program, see MKOB internal structure.
The MKOB telegraph loop consists of four components connected in series.
- the key and sounder
- the keyboard sender
- the code reader
- the internet
The code reader is a passive element, simply responding to the presence or absence of current flowing through the loop and displaying the result as decoded text on the screen. The other three elements have the ability to interrupt the flow of current. If any of the three causes the circuit to open, then no current will flow.
Three variables in the program reflect the state of the three active components. These are kob_latched, keyboard_latched, and internet_latched. If the latched variable is True, that means the corresponding component is in a closed circuit state.
The kob_latched variable reflects whether the shorting switch on the key is closed.
The state of the keyboard_latched variable is determined by whether the keyboard sender has been activated (by pressing the tilde key) or deactivated (by pressing the plus sign). This is how the loop is opened or closed from the keyboard.
As mentioned above, the code reader is a passive component and always represents a closed circuit, so it needs no latching variable.
The internet_latched variable is True if and only if the keys of the remote stations connected to the same wire are all closed. If any remote key is open, internet_latched will be False. In the case where MKOB is not connected to any wire, then internet_latched is True.