EHOCW : Interfaces.

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Keyer to Joystick interface
Keyer to COM port interface
Tranceiver to COM port interface

All to be known about serial interface

Keyer interface on Joystick port

The drawing here below shows the circuit which can be housed into the DB15 connector which could be recovered from an old joystick.The system proceed as if a joystick was connected thanks to the 5K resistors.

In the Windows path ‘Configuration panel ‘ \’Game options’, you find now your keyer as a peripheral like that:

Keyer to serial port interface (COM)

The drawing here below shows the circuit to be used in order to connect the CW keyer to a serial port (COM) of the PC.The idea is to connect the ‘point’ and the ‘dash’ to the CTS and DSR pins which are actually digital ‘inputs’.
Nevertheless, the circuit needs a supply voltage for working, so it is necessary to enable the DTR or RTS which are digital ‘outputs’, otherwise to use an external positive 12 volts DC source ( 12 volts because of RS232, against the pin 5 GROUND)

It is possible to use the same serial port for the keyer input and the tranceiver output , as explain here after :
-RTS is used for the transceiver control(CW manipulation)
-DTR is used for the positive power supply of the keyer
-CTS and RTS are used for the Keyer contacts connection
If you wish to use DTR for the PTT command of the tranceiver , you have to provide an external power source for the keyer power supply.
All these configurations can be set in the menu ‘Tools\Options’

Serial port Tranceiver interface

Here is the very simple connection of the output serial port interface to the tranceiver keyer input.
The drawing does not show the PTT command in order to keep it simple , and also ,as it is the circuit is like a simple keyer which will work with any tranceiver.

The pin 7 is connected to the RTS (Ready To Send) which is driven by the EhoCW software according to the CW code.The optocoupler is a 4N33 from the junkbox , so any equivalent reference will do the job.
The LED flash with the morse code.