Connecting your Transceiver

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All transceivers that support computer control do so via an external interface unit, whose primary purpose is to provide level conversion and isolation or via a built-in true RS-232 interface. The interface unit plugs into the back of your transceiver, and then a lead goes from a serial port on your computer to the interface unit.


You can connect your transceiver via the interface unit to any port that is capable of supporting interrupt handling. This means the port must have a unique IRQ. In most PCs, COM 1 and 2 will work fine, but often the  COM3 and/or COM 4 ports, if fitted either do not have, or share an IRQ line. Such ports cannot be used for the transceiver interface, but could be used for the Morse code keyer output, for example.


Your interface unit to computer cables should be a straight through type, as follows:



TNC and Transceiver interface cables for a 25 way plug



TNC and Transceiver interface cables for a 9 way plug



Please note, however, as a net result TxD and RxD need to be crossed. This is performed in most cases by the interface unit, e.g. IF-232C from KENWOOD. If hardware handshake is to be activated by connecting RTS and CTS on both sides (transceiver and PC) these wires need to be crossed as least as a net result with respect to the interface unit.


This means: An output/transmitting pin on one side of the serial interface must always see an input/receiving pin on the other side. The wiring has to be performed accordingly.


This topic was last edited on  Thursday, 17-Jun-2021,  at  10:49